Associate Professor of Radiology (Nuclear Medicine) at the Stanford University Medical Center

Radiology - Rad/Molecular Imaging Program at Stanford

Bio

Bio

Dr. Iagaru is an Associate Professor of Radiology - Nuclear Medicine and the Chief of the Division of Nuclear Medicine and Molecular Imaging at Stanford Health Care. He completed medical school at Carol Davila University of Medicine, Bucharest, Romania, and an internship at Drexel University College of Medicine, Graduate Hospital, in the Department of Medicine in Philadelphia. He began his residency at the University of Southern California (USC) Keck School of Medicine, Los Angeles, in the Division of Nuclear Medicine, where he was the chief resident. Dr. Iagaru finished his residency and completed a PET/CT fellowship at Stanford University's School of Medicine in the Division of Nuclear Medicine. His research interests include PET/MRI and PET/CT for early cancer detection; clinical translation of novel PET radiopharmaceuticals; peptide-based diagnostic imaging and therapy; and radioimmunotherapy.

Since joining the faculty at Stanford in 2007, Dr. Iagaru has received several awards including the Society of Nuclear Medicine (SNM) 2009 Image of the Year Award; American College of Nuclear Medicine (ACNM) Mid-Winter Conference 2010 Best Essay Award; 2009, 2014 and 2015Western Regional SNM Scientist Award; 2011 SNM Nuclear Oncology Council Young Investigator Award; and a Stanford Cancer Center 2009 Developmental Cancer Research Award in Translational Science. Dr. Iagaru presented more than 100 abstracts at national and international meetings and published more than 100 papers in peer-reviewed journals, as well as 7 book chapters.

Clinical Trials

This study is a prospective, interventional, open-label, multi-center early access program
for the use of Ra-223 Cl2 in HRPC/CRPC patients diagnosed with symptomatic bone metastasis
and to collect additional short and long term safety data on the product.

Stanford is currently not accepting patients for this trial.For more information, please contact Elizabeth Chitouras, 650-498-0623.

Integrin Alpha-v-Beta and [18F]-R01-MG-F2 PET/CT in Measuring Response in Patients With Pancreatic Cancer and Healthy VolunteersRecruiting

This pilot clinical trial studies the use of integrin alpha-v-beta [18F]-R01-MG-F2 Positron
Emission Tomography/Computed Tomography (PET/CT) and Positron Emission Tomography-Magnetic
Resonance Imaging in (PET/MRI) in measuring response in patients with pancreatic cancer and
healthy volunteers. Integrins, such as integrin alpha-v-beta-6 (avb6), are a family of
membrane receptors that are overexpressed on the cell surface of pancreatic cancers.
[18F]-R01-MG-F2 targets avb6, which may improve early detection of and better stratify
treatment options for patients with pancreatic cancer.

The purpose of this study is to
- compare Progression Free Survival (PFS) after treatment with 177Lu-DOTA0-Tyr3-Octreotate
plus best supportive care (30 mg Octreotide LAR) to treatment with high dose (60 mg)
Octreotide LAR in patients with inoperable, progressive (as determined by Response
Evaluation Criteria in Solid Tumors [RECIST] Criteria), somatostatin receptor positive,
well-differentiated neuroendocrine tumours of the small bowel (midgut carcinoid
tumours).
- compare the Objective Response Rate (ORR) between the two study arms
- compare the Overall Survival (OS) between the two study arms
- compare the Time to Tumour Progression (TTP) between the two study arms
- evaluate the safety and tolerability of 177Lu-DOTA0-Tyr3-Octreotate
- evaluate the health related quality of life (QoL) as measured by the European
Organization for Research and Treatment of Cancer (EORTC) QLQ-G.I.NET21 questionnaire
- explore the correlation of toxicity outcomes and administered radiation doses corrected
for body weight and body surface area
- explore the correlation of clinical efficacy outcomes with the levels of the biomarkers
Chromogranin-A (CgA) in the serum and 5-Hydroxyindoleacetic acid (5-HIAA) in the urine
- evaluate dosimetry, pharmacokinetics (PK) and ECG in a subset of 20 patients
- explore the correlation of clinical efficacy outcomes with OctreoScan® tumour uptake
score
- explore the correlation of clinical outcomes with serum levels of Alkaline Phosphatase
(AP)

Stanford is currently not accepting patients for this trial.For more information, please contact Flordeliza Mendoza, 650-724-2056.

Exploration of Tumor Accumulation of BAY94-9392 in Patients With CancerNot Recruiting

The study will be conducted as an open label, single-dose, explorative study with patients
with histologically proven cancer and, preferably, tumor positive lesions in previously
performed nuclear medicine imaging examinations.
The investigational drug will be given as a single administration in a dose of </= 0.1 mg
BAY94-9392 (300 MBq, +/- 10%). The total duration of the study for each patient will be
approximately 8 days.

Stanford is currently not accepting patients for this trial.For more information, please contact Lindee Burton, (650) 725 - 4712.

This clinical trial studies gallium-68 (68Ga)-prostate specific membrane antigen (PSMA)
(gallium Ga 68-labeled PSMA ligand Glu-urea-Lys[Ahx]) positron emission tomography
(PET)/computed tomography (CT) or PET/magnetic resonance imaging (MRI) in identifying
prostate cancer that may have returned after a period of improvement (biochemical
recurrence). 68Ga-PSMA is a radiopharmaceutical that localizes to a specific prostate cancer
receptor, which can then be imaged by the PET/CT or PET/MRI scanner.

Stanford is currently not accepting patients for this trial.For more information, please contact Pamela Gallant, 650-736-8965.

Fluorine-18 Fluorodeoxyglucose (F-18 FDG) PET/CT is established as a powerful imaging tool
for cancer detection and monitoring response to therapy. Sodium Fluorine-18 (F-18) was used
in the 1970s for bone scanning and can be used as a skeletal tracer in current PET/CT
scanners. The combined administration of F-18 and F-18 FDG in a single PET/CT scan for cancer
detection was not attempted to date. We hope to learn what is the best approach for detection
of cancer and thus to improve cancer treatment.

The purpose of the study is to conduct research of a new PET radiopharmaceutical in cancer
patients. We will assess the uptake of this novel radiopharmaceutical in subjects with breast
cancer, lung cancer, glioblastoma multiforme (GBM) and other cancers requiring
antiangiogenesis treatment.

Stanford is currently not accepting patients for this trial.For more information, please contact CCTO, 650-498-7061.

This clinical trial studies sodium fluorine-18 (18F NaF)/fluorine-18 (18F) fluorodeoxyglucose
(FDG) positron emission tomography (PET)/magnetic resonance imaging (MRI) in detecting
skeletal metastases in patients with stage III-IV breast cancer or stage II-IV prostate
cancer. 18F NaF and 18F FDG are radioactive substances that are absorbed by cancerous cells
and allow for the cancer to be found using diagnostic procedures such as PET/MRI. PET/MRI is
a procedure that combines detailed pictures of areas inside the body from PET and MRI scans
and may help find and diagnose skeletal metastases in patients with breast or prostate
cancer. It is not yet known whether 18F NaF/18F FDG PET/MRI is better than standard imaging
methods in detecting skeletal metastases.

This phase II/III trial studies how well gallium (Ga) 68-labeled gastrin-releasing peptide
receptor (GRPR) antagonist BAY86-7548 (68Ga-RM2) positron emission tomography (PET)/magnetic
resonance imaging (MRI) works in detecting prostate cancer in patients with negative computed
tomography (CT) scan and elevated prostate-specific antigen levels after treatment with
surgery or radiation. PET/MRI scans take both PET and MRI images at the same time and combine
them into a single picture and is used to describe information regarding the function, as
well as location and size of a tumor. 68Ga-RM2, a compound made of a radioactive agent linked
to a pharmacological substance that is strongly attracted by a substance made by tumor cells,
to detect prostate cancer. 68Ga-RM2 PET/MRI may be able to see smaller tumors than the
standard of care contrast-enhanced CT or MRI scan

This phase II/III trial studies gallium 68 Ga (68Ga)-prostate-specific membrane antigen
(PSMA) positron emission tomography/magnetic resonance imaging (PET/MRI) in finding tumors in
patients with prostate cancer undergoing surgery that tend to spread quickly
(intermediate-risk) or is likely to come back or spread (high-risk). Diagnostic procedures,
such as PET/MRI, may help find and diagnose prostate cancer and find out how far the disease
has spread. Radioactive drugs, such as gallium Ga 68-PSMA, binds to tumor cells that have
specific receptors, and may allow doctors to see smaller tumors than the standard of care
contrast-enhanced computed tomography (CT) or MRI scan.

The goal of this Phase II clinical trial is to further evaluate the ability of 18F-FSPG to
diagnose, prognosticate, and evaluate response to therapy in patients with a wide variety of
metastatic cancers.

Stanford is currently not accepting patients for this trial.For more information, please contact Phuong Pham, 650-725-9810.

This clinical trial studies the use of gallium-68 (68Ga)-DOTA-Bombesin as the imaging agent
for positron emission tomography (PET)/magnetic resonance imaging (MRI), collectively
PET-MRI, in patients with prostate cancer. PET uses a radioactive substance called
68Ga-DOTA-Bombesin, which attaches to tumor cells with specific receptors on their surfaces.
The PET scanner takes pictures that capture where the radioactive drug is "lighting up" and
attaching to tumor cells, which may help doctors recognize differences between tumor and
healthy prostate tissue. MRI uses radio waves and a magnet to make a picture of areas inside
the body. Using 68Ga-DOTA-Bombesin in diagnostic procedures, such as PET/MRI, may allow
doctors to identify smaller tumors than standard imaging.

Stanford is currently not accepting patients for this trial.For more information, please contact Phuong Pham, 650-725-9810.

This trial studies how well gallium Ga 68-labeled PSMA ligand Glu-urea-Lys(Ahx)-HBED-CC
(68Ga-PSMA) positron emission tomography (PET)/computed tomography (CT) works in detecting
prostate cancer that may have come back in patients with elevated prostate-specific antigen
(PSA) after initial treatment. A rise in blood level of PSA, a protein made by the prostate,
after treatment with surgery or radiation in patients without symptoms indicates that the
cancer may have come back (recurrence). PSA however cannot determine whether the disease is
located only in the prostate or other places in the body. 68Ga-PSMA is a radioactive tracer
that targets and specifically binds to tumor cells expressing PSA making them lighting up.
PET and CT make computerizing pictures of areas inside the body where the radioactive
substance is lighting up. 68Ga-PSMA PET/CT may be able to see smaller tumors than standard
imaging and may help determine whether prostate cancer has come back and where it is in the
body.

Rituximab is an antibody targeted against the CD20 antigen found primarily on B-cells.
Therefore, an imaging agent targeting CD20 expression may provide a more accurate evaluation
of extent of disease and response to therapy than the current standard of care, F-18 FDG
PET/CT.
The main purpose of the study is to investigate a new PET/CT imaging probe for detection and
follow up of lymphoma. Following are the 3 aims of the study: a) Phase I testing in lymphoma
patients of Cu-64 labelled Rituxan for defining normal tracer biodistribution, stability,
pharmacokinetics and radiation dosimetry; b) comparison of Cu-64 Rituxan and F-18 FDG PET/CT
in lymphoma patients; c) evaluation of changes in uptake of Cu-64 Rituxan in response to
rituximab-based treatment in CD20-positive B-cell NHL

Stanford is currently not accepting patients for this trial.For more information, please contact Elizabeth Chitouras, (650) 498 - 0623.

This clinical trial studies how well positron emission tomography (PET)/computed tomography
(CT) works compared to PET/magnetic resonance imaging (MRI) in evaluating patients with
cancer. PET/CT and PET/MRI may determine which scanner is best for the patient's type of
cancer and other types of cancers.

Accurate measurements from a non-invasive test like myocardial perfusion positron emission
tomography/ computed tomography (PET/CT) may decrease the need for invasive procedures such
as cardiac catheterization.The investigators wish to see if the measurements from cardiac
catheterization can be predicted using a non-invasive 13N-NH3 digital PET/CT scan.

The primary objective of the study is to evaluate 68Ga-DOTA TATE PET/CT for staging and
monitoring response to chemotherapy in patients with carcinoid, neuroendocrine tumors,
medullary thyroid cancer and other cancers expressing somatostatin receptors.

The purpose of this study is to compare progression-free survival (PFS) (based upon
investigator assessment using RECIST v1.1) in participants with platinum-resistant ovarian
cancer who receive combination therapy with EC145 and pegylated liposomal doxorubicin
(EC145+PLD) with that in participants who receive PLD and placebo.

Stanford is currently not accepting patients for this trial.For more information, please contact Sharanya Ramasubramanian, 650-723-0622.

Abstract

Our objective was to determine clinically the value of time-of-flight (TOF) information in reducing PET artifacts and improving PET image quality and accuracy in simultaneous TOF PET/MR scanning.A total 65 patients who underwent a comparative scan in a simultaneous TOF PET/MR scanner were included. TOF and non-TOF PET images were reconstructed, clinically examined, compared and scored. PET imaging artifacts were categorized as large or small implant-related artifacts, as dental implant-related artifacts, and as implant-unrelated artifacts. Differences in image quality, especially those related to (implant) artifacts, were assessed using a scale ranging from 0 (no artifact) to 4 (severe artifact).A total of 87 image artifacts were found and evaluated. Four patients had large and eight patients small implant-related artifacts, 27 patients had dental implants/fillings, and 48 patients had implant-unrelated artifacts. The average score was 1.14 ± 0.82 for non-TOF PET images and 0.53 ± 0.66 for TOF images (p?0.01) indicating that artifacts were less noticeable when TOF information was included.Our study indicates that PET image artifacts are significantly mitigated with integration of TOF information in simultaneous PET/MR. The impact is predominantly seen in patients with significant artifacts due to metal implants.

Abstract

Nuclear medicine can play an important role in evaluating prostate cancer combining anatomical and functional information with hybrid techniques. Various PET radiopharmaceuticals have been used for targeting specific biological markers in prostate cancer. Research is ideally oriented towards the development of radiopharmaceuticals targeting antigens overexpressed in prostate cancer, as opposed to normal prostate tissue. In this regard, gastrin-releasing peptide receptors (GRPR) are excellent candidates. Bombesin analogues targeting the GRPR have been investigated. Gallium-68 ((68)Ga) is an interesting PET radioisotope due to several advantages, such as availability, ease of radiochemistry, half-life, and costs. The focus of this review is on (68)Ga-labeled bombesin analogues in prostate cancer.

Abstract

The purpose of this study was to test a method of quantifying skeletal tumour burden with F-NaF PET/CT.We retrospectively reviewed the charts of 117 patients who underwent F-NaF PET/CT for the detection of bone metastases, 68 women and 49 men, 16-82 years old (mean±SD: 62.9±10.7 years). Mean standardized uptake values (SUVmean) were measured in five anatomic sites to evaluate normal skeleton activity. The influence of sex and age was investigated. Skeletal tumour burden was calculated in 69 exams positive for bone metastases using volumetric data and SUVmean values. Intraobserver and interobserver reproducibility was tested. In 10 patients with breast cancer, skeletal tumour burden in pretreatment and post-treatment F-NaF PET/CT was compared with tumour marker and clinical evolution.The range of normal skeleton SUVmean for the 410 volume of interests analysed was 2.2-5.9 (mean±SD: 4.4±1.5). A threshold of 10 was chosen to exclude F-NaF normal skeleton uptake. An inverse relationship was found between normal skeleton SUVmean and age (r=-0.237; P=0.032). Our results show excellent intraobserver and interobserver reproducibility, with intraclass correlation values of 0.995 and 0.997, respectively. The percentage change in the skeletal tumour burden in response to therapy shows a moderate direct correlation with the percentage variation of the tumour marker (r=0.668; P=0.035).The methodology that we used to quantify skeletal tumour burden is easy to perform, highly reproducible and allows for the evaluation of bone tumour response to therapy in a subgroup of breast cancer patients. The possibility of skeletal tumour burden quantification is another advantage of F-NaF PET/CT over the visual and subjective interpretation of bone scintigraphy.

Abstract

To compare the conspicuity of malignant lesions between FDG PET/CT and a new simultaneous, time-of-flight (TOF) enabled PET/MRI scanner.All patients underwent a single-injection of FDG, followed by a dual imaging protocol consisting of PET/CT followed by TOF PET/MRI. PET/CT and PET/MRI images were evaluated by two readers independently for areas of FDG uptake compatible with malignancy, and then categorized into 5 groups (1: PET/MRI and PET/CT positive; 2: PET/MRI positive, PET/CT positive in retrospect; 3: PET/CT positive, PET/MRI positive in retrospect; 4: PET/MRI positive, PET/CT negative; 5: PET/MRI negative, PET/CT positive) by consensus. Patients with no lesions on either study or greater than 10 lesions based on either modality were excluded from the study.Fifty-two patients (mean±SD age: 58±14 years) underwent the dual imaging protocol; of these, 29 patients with a total of 93 FDG-avid lesions met the inclusion criteria. The majority of lesions (56%) were recorded prospectively in the same location on PET/CT and PET/MRI. About an equal small fraction of lesions were seen on PET/CT but only retrospectively on PET/MRI (9%) and vice versa (12%). More lesions were identified only on PET/MRI but not on PET/CT, even in retrospect (96% vs. 81%, respectively; p = 0.003). Discrepant lesions had lower maximum standardized uptake value (SUVmax) than concordant lesions on both modalities (p<0.001).While most lesions were identified prospectively on both modalities, significantly more lesions were identified with PET/MRI than with PET/CT.

Abstract

To evaluate if the new Discovery Molecular Insights (DMI) PET/CT scanner provides equivalent results compared to the standard of care PET/CT scanners (GE Discovery 600 or GE Discovery 690) used in our clinic and to explore any possible differences in semi-quantitative measurements.The local Institutional Review Board approved the protocol and written informed consent was obtained from each patient. Between September and November 2016, 50 patients underwent a single 18F-FDG injection and two scans: the clinical standard PET/CT followed immediately by the DMI PET/CT scan. We measured SUVmax and SUVmean of different background organs and up to four lesions per patient from data acquired using both scanners.DMI PET/CT identified all the 107 lesions detected by standard PET/CT scanners, as well as additional 37 areas of focal increased 18F-FDG uptake. The SUVmax values for all 107 lesions ranged 1.2 to 14.6 (mean ± SD: 2.8 ± 2.8), higher on DMI PET/CT compared with standard of care PET/CT. The mean lesion:aortic arch SUVmax ratio and mean lesion:liver SUVmax ratio were 0.2-15.2 (mean ± SD: 3.2 ± 2.6) and 0.2-8.5 (mean ± SD: 1.9 ± 1.4) respectively, higher on DMI PET/CT than standard PET/CT. These differences were statistically significant (P value < 0.0001) and not correlated to the delay in acquisition of DMI PET data (P < 0.0001).Our study shows high performance of the new DMI PET/CT scanner. This may have a significant role in diagnosing and staging disease, as well as for assessing and monitoring responses to therapies.

Abstract

Imaging plays an important role in prostate cancer (PC), including accurate evaluation of the extent of disease, assessment of sites of recurrent disease, and monitoring of response to treatment. Molecular imaging techniques are among the novel developments related to the imaging of PC, and various SPECT and PET radiopharmaceuticals are now available in clinical trials or commercially. Here we describe the preclinical and clinical use of gastrin-releasing peptide receptors as targets for the imaging of PC, with a focus on the development of PET tracers for the imaging of gastrin-releasing peptide receptor-positive tumors.

Abstract

Although selective metabolic and receptor-based molecular agents will surely be included in the future of prostate cancer diagnosis and therapy, currently available inorganic compounds-such as (18)F-NaF for the diagnosis of bony disease and (223)RaCl2 for the therapy of bone metastases-were recently shown to be superior to standard (99m)Tc-phosphonates for diagnosis and (153)Sm-ethylenediaminetetramethylene phosphonate or (89)SrCl2 for therapy. The advantages of (18)F-NaF include improved lesion detection and, when used in combination with CT, improved diagnostic confidence and specificity. In addition to being the first approved ?-emitter, (223)RaCl2 is the first radiopharmaceutical to show an increase in overall survival, a decrease in skeletal events, palliation of bone pain, and a low profile of adverse reactions (which are mild and manageable). The management of metastatic bone disease with (223)RaCl2 is uniquely satisfying, as patients can be monitored directly during their monthly treatment visits.

Abstract

Extraskeletal findings detected on whole-body low-dose unenhanced computed tomography (CT) as a part of F-NaF PET/CT scans can be numerous and present challenges for further management. Here, we investigate the frequency and clinical significance of extraskeletal findings among 130 consecutive patients undergoing F-NaF PET/CT for osseous metastatic disease.F-NaF PET/CT performed on 130 patients (101 men and 29 women; mean age: 61.4 years) with biopsy-proven malignancies were reviewed independently. Incidental soft tissue findings detected on unenhanced low-dose CT portions of the scans were compiled and categorized by clinical significance.A total of 275 incidental extraskeletal CT findings were observed in 114 out of 130 patients (87.7%). Seven patients (5.4%) showed clinically significant findings. One patient developed new lung nodules that were resected and proven to be metastases. Two patients showed new hypodense hepatic lesions that were highly suspicious for liver metastases. One patient with prostate cancer was found to have previously unknown retroperitoneal lymphadenopathy. Three patients showed indeterminate renal and adrenal lesions that necessitated further correlative imaging.Although CT indicated a large number of incidental extraskeletal lesions in the majority of patients undergoing F-NaF PET/CT, clinically significant incidental findings requiring further evaluation were relatively infrequently observed in 5.4% of patients. Thus, the low-dose unenhanced CT in F-NaF PET/CT performed for oncologic evaluation may indicate unexpected soft tissue lesions that can impact patient management and therefore should be interpreted by physicians skilled in CT reading, with correlation to available imaging, and familiar with established guidelines for work-up of incidental findings.

Abstract

Advances in the understanding of cellular and molecular basis of tumor progression have spurred interest in the development of new targeted agents that are changing the therapeutic management of patients with cancer. In parallel to progression in the therapeutic area, new PET radiopharmaceuticals are being developed to guide the use of such targeted therapies. This article aims to give an overview on the role of PET imaging in the individualized management of patients affected by urologic and gynecologic malignancies, focusing on the most promising targets for therapies and for molecular imaging using PET.

Abstract

As quantitative F-FDG PET numbers and pooling of results from different PET/CT scanners become more influential in the management of patients, it becomes imperative that we fully interrogate differences between scanners to fully understand the degree of scanner bias on the statistical power of studies.Participants with body mass index (BMI) greater than 25, scheduled on a time-of-flight (TOF)-capable PET/CT scanner, had a consecutive scan on a non-TOF-capable PET/CT scanner and vice versa. SUVmean in various tissues and SUVmax of malignant lesions were measured from both scans, matched to each subject. Data were analyzed using a mixed-effects model, and statistical significance was determined using equivalence testing, with P < 0.05 being significant.Equivalence was established in all baseline organs, except the cerebellum, matched per patient between scanner types. Mixed-effects method analysis of lesions, repeated between scan types and matched per patient, demonstrated good concordance between scanner types.Patients could be scanned on either a TOF or non-TOF-capable PET/CT scanner without clinical compromise to quantitative SUV measurements.

Abstract

We report the effect of antiangiogenic therapy on the biodistribution of (18)F-FPPRGD2 (a surrogate biomarker of integrin ?v?3 expression), and the potential of (18)F-FPPRGD2 to predict the prognosis in patients with cervical cancer and ovarian cancer in this clinical scenario.Data from six women, age range 30 - 59 years (mean?±?SD 44.0?±?12.5 years), who had undergone a (18)F-FPPRGD2 PET/CT scan and bevacizumab-containing therapy were prospectively collected and analyzed. We compared baseline (18)F-FPPRGD2 and (18)F-FDG uptake in the lesions and tumor-to-background (T/B) ratios. The maximum and mean (18)F-FPPRGD2 standardized uptake values (SUVmax and SUVmean) were recorded for 13 normal organs, as well as in all the identified malignant lesions on the pretreatment scan and the 1-week post-treatment scan. We also measured changes in (18)F-FPPRGD2 uptake from before to 1 week after treatment, and compared them to the changes in (18)F-FDG uptake from before to 6 weeks after treatment. Treatment outcomes were correlated with these changes.The uptake in lesions and T/B ratio of (18)F-FPPRGD2 were lower than those of (18)F-FDG (SUVmax 3.7?±?1.3 vs. 6.0?±?1.8, P?0.001; SUVmean 2.6?±?0.7 vs. 4.2?±?1.3, P?0.001; T/B ratio based on SUVmax 2.4?±?1.0 vs. 2.6?±?1.0, P?0.04; T/B ratio based on SUVmean 1.9?±?0.6 vs. 2.4?±?1.0, P?0.003). One patient did not return for the follow-up scan and in another patient no lesions were identified on the pretreatment scan. (18)F-FPPRGD2 uptake in lesions in the remaining four patients had significantly changed 1 week after treatment (SUVmean 3.3?±?1.0 vs. 2.7?±?1.0, P?0.001), while uptake in all normal tissues analyzed was not affected by treatment. One patient with clinical disease progression had a decrease in lesional (18)F-FPPRGD2 SUVmean of 1.6 % and in (18)F-FDG SUVmean of 9.4 %. Two patients with a clinical complete response to treatment had decreases in lesional (18)F-FPPRGD2 SUVmean of 25.2 % and 25.0 % and in (18)F-FDG SUVmean of 6.1 % and 71.8 %. One patient with a clinical partial response had a decrease in lesional (18)F-FPPRGD2 SUVmean of 7.9 % and in (18)F-FDG SUVmean of 76.4 %.This pilot study showed that (18)F-FPPRGD2 and (18)F-FDG provide independent information about the biology of ovarian and cervical cancers. Bevacizumab-containing therapy does not affect (18)F-FPPRGD2 uptake in normal organs, but does result in statistically significant changes in lesions. In addition, (18)F-FPPRGD2 may have potential for early prediction of response to such treatments. These preliminary findings have to be confirmed in larger studies.

Abstract

To analyze the biodistribution of Ga-DOTA-TATE in the normal tissues and uptake in benign, indeterminate, and malignant lesions in a population of patients with known neuroendocrine tumors (NET) using semiquantitative standardized uptake values (SUV) measurements.One hundred four consecutively scanned patients (51 men and 53 women; mean age, 56.4 years) with confirmed diagnosis of NET underwent PET/CT 1 hour after administration of Ga-DOTA-TATE. SUVmean, and SUVmax were measured in 37 normal anatomical structures for each patient. Abnormal uptake was divided into benign, indeterminate, and malignant categories based on imaging characteristic, clinical follow-up, and pathology.High physiologic uptake (SUVmax > 7) was observed in spleen, renal parenchyma, adrenal glands, pituitary gland, stomach, and liver (in decreasing order). Moderate uptake (3.5-7) was present in the prostate, jejunum, pancreas, ileum, and salivary glands. Mild uptake (2-3.5) was present in the uterus, colon, thyroid, rectum, and skeleton. A total of 678 lesions (limited to 5 lesions with highest uptake per organ) were included in the analysis, including 127 benign and 54 indeterminate lesions. Uptake was significantly higher in malignant lesions than in benign lesions, but an overlap was noted between the groups.Ga-DOTA TATE uptake in normal and abnormal structures is highly variable in patients with NET. SUV is a useful measure for characterizing benign versus malignant lesions. Anatomical and clinical correlation may be necessary to characterize foci of intermediate uptake.

Abstract

Glu-NH-CO-NH-Lys-(Ahx)-[(68)Ga(HBED-CC)] ((68)Ga-PSMA-11) is a PET tracer that can detect prostate cancer relapses and metastases by binding to the extracellular domain of PSMA.(68)Ga-labeled DOTA-4-amino-1-carboxymethyl-piperidine-d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 ((68)Ga-RM2) is a synthetic bombesin receptor antagonist that targets gastrin-releasing peptide receptors. We present pilot data on the biodistribution of these PET tracers in a small cohort of patients with biochemically recurrent prostate cancer.Seven men (mean age ± SD, 74.3 ± 5.9 y) with biochemically recurrent prostate cancer underwent both(68)Ga-PSMA-11 PET/CT and(68)Ga-RM2 PET/MRI scans. SUVmaxand SUVmeanwere recorded for normal tissues and areas of uptake outside the expected physiologic biodistribution.All patients had a rising level of prostate-specific antigen (mean ± SD, 13.5 ± 11.5) and noncontributory results on conventional imaging.(68)Ga-PSMA-11 had the highest physiologic uptake in the salivary glands and small bowel, with hepatobiliary and renal clearance noted, whereas(68)Ga-RM2 had the highest physiologic uptake in the pancreas, with renal clearance noted. Uptake outside the expected physiologic biodistribution did not significantly differ between(68)Ga-PSMA-11 and(68)Ga-RM2; however,(68)Ga-PSMA-11 localized in a lymph node and seminal vesicle in a patient with no abnormal(68)Ga-RM2 uptake. Abdominal periaortic lymph nodes were more easily visualized by(68)Ga-RM2 in two patients because of lack of interference by radioactivity in the small intestine.(68)Ga-PSMA-11 and(68)Ga-RM2 had distinct biodistributions in this small cohort of patients with biochemically recurrent prostate cancer. Additional work is needed to understand the expression of PSMA and gastrin-releasing peptide receptors in different types of prostate cancer.

Abstract

This study evaluated the potential of Q.Freeze algorithm for reducing motion artifacts, in comparison with ungated imaging (UG) and respiratory-gated imaging (RG).Twenty-nine patients with 53 lesions who had undergone RG F-FDG PET/CT were included in this study. Using PET list mode data, five series of PET images [UG, RG, and QF images with an acquisition duration of 3?min (QF3), 5?min (QF5), and 10?min (QF10)] were reconstructed retrospectively. The image quality was evaluated first. Next, quantitative metrics [maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), SD, metabolic tumor volume, signal to noise ratio, or lesion to background ratio] were calculated for the liver, background, and each lesion, and the results were compared across the series.QF10 and QF5 showed better image quality compared with all other images. SUVmax in the liver, background, and lesions was lower with QF10 and QF5 than with the others, but there were no statistically significant differences in SUVmean and the lesion to background ratios. The SD with UG and RG was significantly higher than that with QF5 and QF10. The metabolic tumor volume in QF3 and QF5 was significantly lower than that in UG.The Q.Freeze algorithm can improve the quality of PET imaging compared with RG and UG.

Abstract

(S)-4-(3-[18F]Fluoropropyl)-L-glutamic acid (18F-FSPG) is a novel radiopharmaceutical for Positron Emission Tomography (PET) imaging. It is a glutamate analogue that can be used to measure xC- transporter activity. This study was performed to assess the feasibility of 18F-FSPG for imaging orthotopic brain tumors in small animals and the translation of this approach in human subjects with intracranial malignancies.For the small animal study, GS9L glioblastoma cells were implanted into brains of Fischer rats and studied with 18F-FSPG, the 18F-labeled glucose derivative 18F-FDG and with the 18F-labeled amino acid derivative 18F-FET. For the human study, five subjects with either primary or metastatic brain cancer were recruited (mean age 50.4 years). After injection of 300 MBq of 18F-FSPG, 3 whole-body PET/Computed Tomography (CT) scans were obtained and safety parameters were measured. The three subjects with brain metastases also had an 18F-FDG PET/CT scan. Quantitative and qualitative comparison of the scans was performed to assess kinetics, biodistribution, and relative efficacy of the tracers.In the small animals, the orthotopic brain tumors were visualized well with 18F-FSPG. The high tumor uptake of 18F-FSPG in the GS9L model and the absence of background signal led to good tumor visualization with high contrast (tumor/brain ratio: 32.7). 18F-FDG and 18F-FET showed T/B ratios of 1.7 and 2.8, respectively. In the human pilot study, 18F-FSPG was well tolerated and there was similar distribution in all patients. All malignant lesions were positive with 18F-FSPG except for one low-grade primary brain tumor. In the 18F-FSPG-PET-positive tumors a similar T/B ratio was observed as in the animal model.18F-FSPG is a novel PET radiopharmaceutical that demonstrates good uptake in both small animal and human studies of intracranial malignancies. Future studies on larger numbers of subjects and a wider array of brain tumors are planned.ClinicalTrials.gov NCT01186601.

Abstract

The aim of this study was to investigate the biodistribution of 2-fluoropropionyl-labeled PEGylated dimeric arginine-glycine-aspartic acid (RGD) peptide (PEG3-E[c{RGDyk}]2) ((18)F-FPPRGD2) in cancer patients and to compare its uptake in malignant lesions with (18)F-FDG uptake.A total of 35 patients (11 men, 24 women, mean age 52.1?±?10.8 years) were enrolled prospectively and had (18)F-FPPRGD2 PET/CT prior to treatment. Maximum standardized uptake values (SUVmax) and mean SUV (SUVmean) were measured in 23 normal tissues in each patient, as well as in known or suspected cancer lesions. Differences between (18)F-FPPRGD2 uptake and (18)F-FDG uptake were also evaluated in 28 of the 35 patients.Areas of high (18)F-FPPRGD2 accumulation (SUVmax range 8.9 - 94.4, SUVmean range 7.1 - 64.4) included the bladder and kidneys. Moderate uptake (SUVmax range 2.1 - 6.3, SUVmean range 1.1 - 4.5) was found in the choroid plexus, salivary glands, thyroid, liver, spleen, pancreas, small bowel and skeleton. Compared with (18)F-FDG, (18)F-FPPRGD2 showed higher tumor-to-background ratio in brain lesions (13.4?±?8.5 vs. 1.1?±?0.5, P?0.001), but no significant difference in body lesions (3.2?±?1.9 vs. 4.4?±?4.2, P?=?0.10). There was no significant correlation between the uptake values (SUVmax and SUVmean) for (18)F FPPRGD2 and those for (18)F-FDG.The biodistribution of (18)F-FPPRGD2 in cancer patients is similar to that of other RGD dimer peptides and it is suitable for clinical use. The lack of significant correlation between (18)F-FPPRGD2 and (18)F-FDG uptake confirms that the information provided by each PET tracer is different.

Abstract

The combined administration of F-NaF and F-FDG in a single PET/CT scan has the potential to improve patient convenience and cancer detection. Here we report the use of this approach for patients with sarcomas.This is a retrospective review of 21 patients (12 men, 9 women; age, 19-66 years) with biopsy-proven sarcomas who had separate F-NaF PET/CT, F-FDG PET/CT, and combined F-NaF/F-FDG PET/CT scans for evaluation of malignancy. Two board-certified nuclear medicine physicians and 1 board-certified musculoskeletal radiologist were randomly assigned to review the scans. Results were analyzed for sensitivity and specificity, using linear regression and receiver operating characteristics.A total of 13 patients had metastatic disease on F-NaF PET/CT, F-FDG PET/CT, and combined F-NaF/F-FDG PET/CT. Skeletal disease was more extensive on the F-NaF PET/CT scan than on the F-FDG PET/CT in 3 patients, whereas in 1 patient, F-FDG PET/CT showed skeletal disease and the F-NaF PET/CT was negative. Extraskeletal lesions were detected on both F-FDG and combined F-NaF/F-FDG PET/CT in 20 patients, with 1 discordant finding in the lung.The combined F-NaF/F-FDG PET/CT scan allows for accurate evaluation of sarcoma patients. Further evaluation of this proposed imaging modality is warranted to identify the most suitable clinical scenarios, including initial treatment strategy and evaluation of response to therapy.

Abstract

Fusion dual-tracer SPECT imaging enables physiological rather than morphological voxel-based partitioning and dosimetry for (90)Y hepatic radioembolization (RE). We evaluated its prognostic value in a large heterogeneous cohort of patients with extensive hepatic malignancy.A total of 122 patients with primary or secondary liver malignancy (18 different cell types) underwent SPECT imaging after intraarterial injection of (99m)Tc macroaggregated albumin (TcMAA) as a simulation of subsequent (90)Y microsphere distribution, followed by administration of an excess of intravenous (99m)Tc-labelled sulphur colloid (TcSC) as a biomarker for functional liver, and a second SPECT scan. TcMAA distribution was used to estimate (90)Y radiation absorbed dose in tumour (D T) and in functional liver. Laboratory and clinical follow-up were recorded for 12 weeks after RE, and radiographic responses according to (m)RECIST were evaluated at 3 and 6 months. Dose-response relationships were determined for efficacy and toxicity.Patients were treated with a median of 1.73 GBq activity of resin microspheres (98 patients) or glass microspheres (24 patients), in a whole-liver approach (97 patients) or a lobar approach (25 patients). The objective response rate was 41 % at 3 months and 48 % at 6 months. Response was correlated with D T (P?0.01). Median overall survival was 10.1 months (95 % confidence interval 7.4 - 12.8 months). Responders lived for 36.0 months compared to 8.7 months for nonresponders (P?0.01). Stratified for tumour cell type, D T was independently associated with survival (P?0.01). Absorbed dose in functional liver was correlated with toxicity grade change (P?0.05) and RE-induced liver disease (P?0.05).Fusion dual-tracer SPECT imaging offers a physiology-based functional imaging tool to predict efficacy and toxicity of RE. This technique can be refined to define dosing thresholds for specific tumour types and treatments, but appears generally predictive even in a heterogeneous cohort.

Abstract

In this study we evaluated the biodistribution of the (18)F-/(18)F-FDG administration compared to separate (18)F-NaF and (18)F-FDG. We also estimated the interaction of (18)F-NaF and (18)F-FDG in the (18)F-/(18)F-FDG administration by semiquantitative analysis.We retrospectively analyzed data of 49 patients (male 39, female 10; mean ± SD age: 59.3 ± 15.2 years) who had separate (18)F-FDG PET/CT and (18)F-NaF PET/CT, as well as the (18)F-/(18)F-FDG PET/CT sequentially. The most common primary diagnosis was prostate cancer (n = 28), followed by sarcoma (n = 9) and breast cancer (n = 6). The mean standardized uptake values (SUVmean) were recorded for 18 organs in all patients, while maximum SUV (SUVmax) and SUVmean were recorded for all the identified malignant lesions. We also estimated the (18)F-/(18)F-FDG uptake by sum of (18)F-FDG uptake and adjusted (18)F-NaF uptake based on the ratio of (18)F-NaF injected dose in (18)F-/(18)F-FDG PET/CT. Lastly, we compared the results in order to explore the interaction of (18)F-FDG and (18)F-NaF uptake in the (18)F-/(18)F-FDG scan.The (18)F-/(18)F-FDG uptake in the cerebral cortex, cerebellum, parotid grand, myocardium and bowel mostly reflect the (18)F-FDG uptake, while the uptake in the other analyzed structures is influenced by both the (18)F-FDG and the (18)F-NaF uptake. The (18)F-/(18)F-FDG uptake in extra skeletal lesions shows no significant difference when compared to the uptake from the separate (18)F-FDG scan. The (18)F-/(18)F-FDG uptake in skeletal lesions reflected mostly the (18)F-NaF uptake. Tumor to background (T/B) ratio of (18)F-/(18)F-FDG in extra skeletal lesions showed no significant difference when compared with that from (18)F-FDG alone (P = 0.73). For skeletal lesions, T/B ratio of (18)F-/(18)F-FDG was lower than that from (18)F-NaF alone (P <0.001); however, this difference did not result in missed skeletal lesions on the (18)F-/(18)F-FDG scan.The understanding of the biodistribution of radiopharmaceuticals and the lesions uptake of the (18)F-/(18)F-FDG scan, as well as the variations compared to the uptake on the separate (18)F-FDG PET/CT and (18)F-NaF PET/CT are valuable for more in depth evaluation of the combined scanning technique.

Abstract

The purpose of this study was to analyze the distribution of F Sodium Fluoride (F-NaF) uptake in the normal skeleton, benign and malignant bone lesions, and extraskeletal tissues, using semiquantitative SUV measurements.We retrospectively analyzed data from 129 patients who had F-NaF PET/CT at our institution for an oncological diagnosis between 2007 and 2014. There were 99 men and 30 women, 19 to 90 years old (mean [SD], 61.5 [15.5]). The range, average, and SD of SUV were measured for normal bone and extraskeletal tissues uptake for the entire patient population. A separate statistical analysis was performed to compare group A, which corresponds to the population of patient with no F-NaF-avid metastatic lesions, and group B, which corresponds to the population of patient with F-NaF-avid metastatic lesions. We also measured SUVmax and SUVmean for bony metastases and degenerative changesThe PET/CT images were acquired at 30 to 169 minutes (mean [SD], 76.5 [22.8]) after injection of 3.9 to 13.6 mCi (mean [SD], 7.3 [2.4]) of F-NaF. The range and mean (SD) of SUVmax for F-NaF-avid metastasis were 4.5 to 103.3 and 25.9 (16.6) and for F-NaF-avid degenerative changes were 3.3 to 52.1 and 16.5 (7.9), respectively.Various skeletal sites have different normal SUVs. Skeletal metastases have different SUVs when compared with benign findings such as degenerative changes.

Abstract

Methods for calculating the activity to be administered during yttrium-90 radioembolization (RE) are largely based on empirical toxicity and efficacy analyses, rather than dosimetry. At the same time, it is recognized that treatment planning based on proper dosimetry is of vital importance for the optimization of the results of RE. The heterogeneous and often clustered intrahepatic biodistribution of millions of point-source radioactive particles poses a challenge for dosimetry. Several studies found a relationship between absorbed doses and treatment outcome, with regard to both toxicity and efficacy. This should ultimately lead to improved patient selection and individualized treatment planning. New calculation methods and imaging techniques and a new generation of microspheres for image-guided RE will all contribute to these improvements. The aim of this review is to give insight into the latest and most important developments in RE dosimetry and to suggest future directions on patient selection, individualized treatment planning, and study designs.

Abstract

Sodium fluoride PET (F-NaF) has recently reemerged as a valuable method for detection of osseous metastasis, with recent work highlighting the potential of coadministered F-NaF and F-FDG PET/CT in a single combined imaging examination. We further examined the potential of such combined examinations by comparing dual tracer F-NaF/F-FDG PET/CT with CT alone for detection of osseous metastasis.Seventy-five participants with biopsy-proven malignancy were consecutively enrolled from a single center and underwent combined F-NaF/F-FDG PET/CT and diagnostic CT scans. PET/CT as well as CT only images were reviewed in blinded fashion and compared with the results of clinical, imaging, or histological follow-up as a truth standard.Sensitivity of the combined F-NaF/F-FDG PET/CT was higher than that of CT alone (97.4% vs 66.7%). CT and F-NaF/F-FDG PET/CT were concordant in 73% of studies. Of 20 discordant cases, F-NaF/F-FDG PET/CT was correct in 19 (95%). Three cases were interpreted concordantly but incorrectly, and all 3 were false positives. A single case of osseous metastasis was detected by CT alone, but not by F-NaF/F-FDG PET/CT.Combined F-NaF/F-FDG PET/CT outperforms CT alone and is highly sensitive and specific for detection of osseous metastases. The concordantly interpreted false-positive cases demonstrate the difficulty of distinguishing degenerative from malignant disease, whereas the single case of metastasis seen on CT but not PET highlights the need for careful review of CT images in multimodality studies.

Abstract

A 56-year-old woman with prior esophageal resection and reconstruction after accidental lye ingestion presented for management of recently diagnosed thyroid cancer. She had total thyroidectomy with pathology demonstrating bilateral well-differentiated papillary thyroid cancer measuring up to 1.0 cm and positive margins. Approximately 1 month after surgery, I whole-body scan was obtained. Planar images demonstrated linear I uptake in the thorax, compatible with accumulation in the neoesophagus. Given the patient's postsurgical anatomy, SPECT/CT of the thorax was done and demonstrated additional focal I uptake in the left lower neck, compatible with residual thyroid tissue versus thyroid cancer (lymph node metastasis).

Abstract

AbstractManufacturing of 64Cu-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-rituximab injection under good manufacturing practices (GMP) was validated for imaging of patients with CD20+ B-cell non-Hodgkin lymphoma. Rituximab was purified by size exclusion high performance liquid chromatography (HPLC) and conjugated to DOTA-mono-(N-hydroxysuccinimidyl) ester. 64CuCl2, buffers, reagents, and other raw materials were obtained as high-grade quality. Following a semi-automated synthesis of 64Cu-DOTA-rituximab, a series of quality control tests was performed. The product was further tested in vivo using micro-positron emission tomography/computed tomography (PET/CT) to assess targeting ability towards human CD20 in transgenic mice. Three batches of 64Cu-DOTA-rituximab final product were prepared as per GMP specifications. The radiolabeling yield from these batches was 93.1 ± 5.8%; these provided final product with radiopharmaceutical yield, purity, and specific activity of 59.2 ± 5.1% (0.9 ± 0.1 GBq of 64Cu), > 95% (by HPLC and radio-thin layer chromatography), and 229.4 ± 43.3 GBq/µmol (or 1.5 ± 0.3 MBq/µg), respectively. The doses passed apyrogenicity and human serum stability specifications, were sterile up to 14 days, and retained > 60% immunoreactivity. In vivo micro-PET/CT mouse images at 24 hours postinjection showed that the tracer targeted the intended sites of human CD20 expression. Thus, we have validated the manufacturing of GMP grade 64Cu-DOTA-rituximab for injection in the clinical setting.

Abstract

The recent introduction of hybrid PET/MRI scanners in clinical practice has shown promising initial results for several clinical scenarios. However, the first generation of combined PET/MRI lacks time-of-flight (TOF) technology. Here we report the results of the first patients to be scanned on a completely novel fully integrated PET/MRI scanner with TOF.We analyzed data from patients who underwent a clinically indicated F FDG PET/CT, followed by PET/MRI. Maximum standardized uptake values (SUVmax) were measured from F FDG PET/MRI and F FDG PET/CT for lesions, cerebellum, salivary glands, lungs, aortic arch, liver, spleen, skeletal muscle, and fat. Two experienced radiologists independently reviewed the MR data for image quality.Thirty-six patients (19 men, 17 women, mean [±standard deviation] age of 61 ± 14 years [range: 27-86 years]) with a total of 69 discrete lesions met the inclusion criteria. PET/CT images were acquired at a mean (±standard deviation) of 74 ± 14 minutes (range: 49-100 minutes) after injection of 10 ± 1 mCi (range: 8-12 mCi) of F FDG. PET/MRI scans started at 161 ± 29 minutes (range: 117 - 286 minutes) after the F FDG injection. All lesions identified on PET from PET/CT were also seen on PET from PET/MRI. The mean SUVmax values were higher from PET/MRI than PET/CT for all lesions. No degradation of MR image quality was observed.The data obtained so far using this investigational PET/MR system have shown that the TOF PET system is capable of excellent performance during simultaneous PET/MR with routine pulse sequences. MR imaging was not compromised. Comparison of the PET images from PET/CT and PET/MRI show no loss of image quality for the latter. These results support further investigation of this novel fully integrated TOF PET/MRI instrument.

Abstract

These NCCN Guidelines Insights focus on some of the major updates to the 2014 NCCN Guidelines for Thyroid Carcinoma. Kinase inhibitor therapy may be used to treat thyroid carcinoma that is symptomatic and/or progressive and not amenable to treatment with radioactive iodine. Sorafenib may be considered for select patients with metastatic differentiated thyroid carcinoma, whereas vandetanib or cabozantinib may be recommended for select patients with metastatic medullary thyroid carcinoma. Other kinase inhibitors may be considered for select patients with either type of thyroid carcinoma. A new section on "Principles of Kinase Inhibitor Therapy in Advanced Thyroid Cancer" was added to the NCCN Guidelines to assist with using these novel targeted agents.

Abstract

Post-transplant lymphoproliferative disorder (PTLD) describes a spectrum of conditions with highest incidence in the first year post-solid organ transplant in pediatric patients. Central nervous system (CNS) involvement with PTLD carries high mortality risk with no consensus on optimal therapeutic regimen. We present the case of a 7-year old heart transplant patient diagnosed with widespread monomorphic, CD20+, Epstein-Barr virus-positive PTLD, including CNS involvement. In addition to immunosuppression reduction and rituximab, she was treated with multiagent systemic and intrathecal chemotherapy. She achieved a prompt and complete clinical and radiologic remission, which has been sustained for over 46 months since diagnosis.

Abstract

Circulating tumor microemboli (CTM) are potentially important cancer biomarkers, but using them for cancer detection in early-stage disease has been assay limited. We examined CTM test performance using a sensitive detection platform to identify stage I non-small-cell lung cancer (NSCLC) patients undergoing imaging evaluation.First, we prospectively enrolled patients during 18F-FDG PET-CT imaging evaluation for lung cancer that underwent routine phlebotomy where CTM and circulating tumor cells (CTCs) were identified in blood using nuclear (DAPI), cytokeratin (CK), and CD45 immune-fluorescent antibodies followed by morphologic identification. Second, CTM and CTC data were integrated with patient (age, gender, smoking, and cancer history) and imaging (tumor diameter, location in lung, and maximum standard uptake value [SUVmax]) data to develop and test multiple logistic regression models using a case-control design in a training and test cohort followed by cross-validation in the entire group.We examined 104 patients with NSCLC, and the subgroup of 80 with stage I disease, and compared them to 25 patients with benign disease. Clinical and imaging data alone were moderately discriminating for all comers (Area under the Curve [AUC] = 0.77) and by stage I disease only (AUC = 0.77). However, the presence of CTM combined with clinical and imaging data was significantly discriminating for diagnostic accuracy in all NSCLC patients (AUC = 0.88, p value = 0.001) and for stage I patients alone (AUC = 0.87, p value = 0.002).CTM may add utility for lung cancer diagnosis during imaging evaluation using a sensitive detection platform.

Abstract

Post-transplant lymphoproliferative disorder (PTLD) is a rare but serious complication in transplant patients. Although fluorine-18 2-fluoro-2-deoxyglucose PET and computed tomography (F-FDG PET/CT) has been used for the evaluation and management of patients with PTLD, its utility has yet to be documented. We were therefore prompted to review our experience with F-FDG PET/CT in PTLD.We retrospectively reviewed the records of consecutive patients who had undergone F-FDG PET/CT for evaluation of PTLD from January 2004 to June 2012 at our institution. F-FDG PET/CT scans were compared with other imaging modalities performed concurrently. A chart review of pertinent clinical information was also conducted.A total of 30 patients were identified (14 female and 16 male; 1.7-76.7 years of age, average: 23.8 years). Twenty-seven participants had biopsy-proven PTLD and another three had been treated for PTLD because of high clinical suspicion of disease and positive F-FDG PET/CT findings in the absence of histological diagnosis. Eighty-three percent of these PTLD patients had extranodal involvement. In 57% of the cases, F-FDG PET/CT detected occult lesions not identified on other imaging modalities or suggested PTLD in equivocal lesions. The more aggressive PTLD histological subtypes demonstrated higher SUVmax compared with the less aggressive subtypes.F-FDG PET/CT is beneficial in the diagnostic evaluation of patients with PTLD. F-FDG PET/CT has the ability to detect occult lesions not identified on other imaging modalities, particularly extranodal lesions. In addition, F-FDG PET/CT may predict the PTLD subtype, as the lesions with higher pathologic grade presented with significantly higher SUVmax compared with the less aggressive forms.

The Clinical Use of PET/CT in the Evaluation of Melanoma.Methods in molecular biology (Clifton, N.J.)Keu, K. V., Iagaru, A. H.2014; 1102: 553-580

Abstract

Positron emission tomography combined with computed tomography (PET/CT) has emerged in the last decade as a dominant imaging modality used for staging, monitoring response and surveillance of various cancers, including melanoma. Using 2-deoxy-2-((18)F)fluoro-D-glucose ((18)F-FDG) as the radiopharmaceutical, PET/CT has demonstrated its efficacy and its utility in the management of patients with advanced melanoma. Nonetheless, challenges remain in the early stage evaluation of melanoma and in the development of novel radiotracers to better characterize lesions found on PET/CT. This chapter focuses on the advantages and limitations of this imaging modality in melanoma. We also detail and describe the approach to perform (18)F-FDG PET/CT, the methods to accurately quantify lesions, as well as the pearls/pitfalls of image interpretation. Finally, an overview of preclinical and investigational clinical radiopharmaceuticals is presented.

Abstract

INTRODUCTION: A root cause analysis was performed on the occurrence of gastroduodenal ulceration after hepatic radioembolization (RE). We aimed to identify the risk factors in the treated population and to determine the specific mechanism of nontarget RE in individual cases. METHODS: The records of 247 consecutive patients treated with yttrium-90 RE for primary (n = 90) or metastatic (n = 157) liver cancer using either resin (n = 181) or glass (n = 66) microspheres were reviewed. All patients who developed a biopsy-proven microsphere-induced gastroduodenal ulcer were identified. Univariate and multivariate analyses were performed on baseline parameters and procedural data to determine possible risk factors in the total population. Individual cases were analyzed to ascertain the specific cause, including identification of the culprit vessel(s) leading to extrahepatic deposition of the microspheres. RESULTS: Eight patients (3.2 %) developed a gastroduodenal ulcer. Stasis during injection was the strongest independent risk factor (p = 0.004), followed by distal origin of the gastroduodenal artery (p = 0.004), young age (p = 0.040), and proximal injection of the microspheres (p = 0.043). Prolonged administrations, pain during administration, whole liver treatment, and use of resin microspheres also showed interrelated trends in multivariate analysis. Retrospective review of intraprocedural and postprocedural imaging showed a probable or possible culprit vessel, each a tiny complex collateral vessel, in seven patients. CONCLUSION: Proximal administrations and those resulting in stasis of flow presented increased risk for gastroduodenal ulceration. Patients who had undergone bevacizumab therapy were at high risk for developing stasis.

Abstract

Planning hepatic (90)Y radioembolization activity requires balancing toxicity with efficacy. We developed a dual-tracer SPECT fusion imaging protocol that merges data on radioactivity distribution with physiologic liver mapping.Twenty-five patients with colorectal carcinoma and bilobar liver metastases received whole-liver radioembolization with resin microspheres prescribed as per convention (mean administered activity, 1.69 GBq). As part of standard treatment planning, all patients underwent SPECT imaging after intraarterial injection of 37 MBq of (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) to simulate subsequent (90)Y distribution. Immediately afterward, patients received 185 MBq of labeled sulfur colloid ((99m)Tc-SC) intravenously as a biomarker for normal hepatic reticuloendothelial function and SPECT was repeated. The SPECT images were coregistered and fused. A region-based method was used to predict the (90)Y radiation absorbed dose to functional liver tissue (DFL) by calculation of (99m)Tc-MAA activity in regions with (99m)Tc-SC uptake. Similarly, the absorbed dose to tumor (DT) was predicted by calculation of (99m)Tc-MAA activity in voxels without (99m)Tc-SC uptake. Laboratory data and radiographic response were measured for 3 mo, and the survival of patients was recorded. SPECT-based DT and DFL were correlated with parameters of toxicity and efficacy.Toxicity, as measured by increase in serum liver enzymes, correlated significantly with SPECT-based calculation of DFL at all time points (P < 0.05) (mean DFL, 27.9 Gy). Broad biochemical toxicity (>50% increase in all liver enzymes) occurred at a DFL of 24.5 Gy and above. In addition, in uni- and multivariate analysis, SPECT-based calculation of DT (mean DT, 44.2 Gy) correlated with radiographic response (P < 0.001), decrease in serum carcinoembryonic antigen (P < 0.05), and overall survival (P < 0.01). The cutoff value of DT for prediction of 1-y survival was 55 Gy (area under the receiver-operating-characteristic curve = 0.86; P < 0.01). Patients who received a DT of more than 55 Gy had a median survival of 32.8 mo, compared with 7.2 mo in patients who received less (P < 0.05).Dual-tracer (99m)Tc-MAA-(99m)Tc-SC fusion SPECT offers a physiology-based imaging tool with significant prognostic power that may lead to improved personalized activity planning.

Abstract

PURPOSE: Repeated radioembolization (RE) treatments carry theoretically higher risk of radiation-induced hepatic injury because of the liver's cumulative memory of previous exposure. We performed a retrospective safety analysis on patients who underwent repeated RE. METHODS: From 2004 to 2011, a total of 247 patients were treated by RE. Eight patients (5 men, 3 women, age range 51-71 years) underwent repeated treatment of a targeted territory, all with resin microspheres (SIR-Spheres; Sirtex, Lane Cove, Australia). Adverse events were graded during a standardized follow-up. In addition, the correlation between the occurrence of RE-induced liver disease (REILD) and multiple variables was investigated in univariate and multivariate analyses in all 247 patients who received RE. RESULTS: Two patients died shortly after the second treatment (at 84 and 107 days) with signs and symptoms of REILD. Both patients underwent whole liver treatment twice (cumulative doses 3.08 and 2.66 GBq). The other 6 patients demonstrated only minor toxicities after receiving cumulative doses ranging from 2.41 to 3.88 GBq. All patients experienced objective tumor responses. In the whole population, multifactorial analysis identified three risk factors associated with REILD: repeated RE (p = 0.036), baseline serum total bilirubin (p = 0.048), and baseline serum aspartate aminotransferase (p = 0.043). Repeated RE proved to be the only independent risk factor for REILD in multivariate analysis (odds ratio 9.6; p = 0.002). Additionally, the administered activity per target volume (in GBq/L) was found to be an independent risk factor for REILD, but only in whole liver treatments (p = 0.033). CONCLUSION: The risk of REILD appears to be elevated for repeated RE. Objective tumor responses were observed, but establishment of safety limits will require improvement in dosimetric measurement and prediction.

Abstract

OBJECTIVE. Tumor growth and progression require the formation of new blood vessels from preexisting vasculature, a process called angiogenesis. The ability to noninvasively visualize angiogenesis may provide new opportunities to more appropriately select patients for antiangiogenesis treatment and to monitor treatment efficacy. CONCLUSION. The superior molecular sensitivity of PET and the lack of radiation from MRI and contrast-enhanced ultrasound put these techniques at the forefront of clinical translation.

Abstract

The aim of this study was to compare Tc-MDP bone scanning, F NaF PET/CT, F FDG PET/CT, and whole-body MRI (WBMRI) for detection of known osseous metastases.This prospective pilot trial (September 2007-April 2009) enrolled 10 participants (5 men, 5 women, 47-81 years old) diagnosed with cancer and known osseous metastases. F NaF PET/CT, F FDG PET/CT, and WBMRI were performed within 1 month for each participant.The image quality and evaluation of extent of disease were superior by F NaF PET/CT compared to Tc-MDP scintigraphy in all patients with skeletal lesions and compared to F FDG PET/CT in 3 of the patients with skeletal metastases. F NaF PET/CT showed osseous metastases where F FDG PET/CT was negative in another 3 participants. Extraskeletal metastases were identified by F FDG PET/CT in 6 participants. WBMRI with the combination of iterative decomposition of water and fat with echo asymmetry and least-squares estimation, short tau inversion recovery, and diffusion-weighted imaging pulse sequences showed fewer lesions than F NaF PET/CT in 5 patients, same number of lesions in 2 patients, and more lesions in 1 patient. WBMRI showed fewer lesions than F FDG in 3 patients and same lesions in 6 patients.Our pilot phase prospective trial demonstrated superior image quality and evaluation of skeletal disease extent with F NaF PET/CT compared to Tc-MDP scintigraphy and F FDG PET/CT, as well as the feasibility of multisequence WBMRI. In addition, F FDG PET/CT provided valuable soft-tissue information that can change disease management. Further evaluation of these findings using the recently introduced PET/MRI scanners is warranted.

Abstract

(18)F-FDG PET/CT is used in a variety of cancers, but because of variable rates of glucose metabolism, not all cancers are reliably identified. (18)F(-) PET/CT allows for the acquisition of highly sensitive and specific images of the skeleton. We prospectively evaluated combined (18)F(-)/(18)F-FDG as a single PET/CT examination for evaluation of cancer patients and compared it with separate (18)F(-) PET/CT and (18)F-FDG PET/CT scans.One hundred fifteen participants with cancer were prospectively enrolled in an international multicenter trial evaluating (18)F(-) PET/CT, (18)F-FDG PET/CT, and combined (18)F(-)/(18)F-FDG PET/CT. The 3 PET/CT scans were performed sequentially within 4 wk of one another for each patient.(18)F(-)/(18)F-FDG PET/CT allowed for accurate interpretation of radiotracer uptake outside the skeleton, with findings similar to those of (18)F-FDG PET/CT. In 19 participants, skeletal disease was more extensive on (18)F(-) PET/CT and (18)F(-)/(18)F-FDG PET/CT than on (18)F-FDG PET/CT. In another 29 participants, (18)F(-) PET/CT and (18)F(-)/(18)F-FDG PET/CT showed osseous metastases where (18)F-FDG PET/CT was negative. The extent of skeletal lesions was similar in 18 participants on all 3 scans.This trial demonstrated that combined (18)F(-)/(18)F-FDG PET/CT shows promising results when compared with separate (18)F(-) PET/CT and (18)F-FDG PET/CT for evaluation of cancer patients. This result opens the possibility for improved patient care and reduction in health-care costs, as will be further evaluated in future trials.

Abstract

We investigated the relationship of circulating tumor cells (CTCs) in non-small cell lung cancer (NSCLC) with tumor glucose metabolism as defined by (18)F-fluorodeoxyglucose (FDG) uptake since both have been associated with patient prognosis.We performed a retrospective screen of patients at four medical centers who underwent FDG PET-CT imaging and phlebotomy prior to a therapeutic intervention for NSCLC. We used an Epithelial Cell Adhesion Molecule (EpCAM) independent fluid biopsy based on cell morphology for CTC detection and enumeration (defined here as High Definition CTCs or "HD-CTCs"). We then correlated HD-CTCs with quantitative FDG uptake image data calibrated across centers in a cross-sectional analysis.We assessed seventy-one NSCLC patients whose median tumor size was 2.8 cm (interquartile range, IQR, 2.0-3.6) and median maximum standardized uptake value (SUVmax) was 7.2 (IQR 3.7-15.5). More than 2 HD-CTCs were detected in 63% of patients, whether across all stages (45 of 71) or in stage I disease (27 of 43). HD-CTCs were weakly correlated with partial volume corrected tumor SUVmax (r?=?0.27, p-value?=?0.03) and not correlated with tumor diameter (r?=?0.07; p-value?=?0.60). For a given partial volume corrected SUVmax or tumor diameter there was a wide range of detected HD-CTCs in circulation for both early and late stage disease.CTCs are detected frequently in early-stage NSCLC using a non-EpCAM mediated approach with a wide range noted for a given level of FDG uptake or tumor size. Integrating potentially complementary biomarkers like these with traditional patient data may eventually enhance our understanding of clinical, in vivo tumor biology in the early stages of this deadly disease.

Abstract

Surveillance FDG PET/CT was performed in a 75-year-old woman with history of melanoma and colon cancer. She had rash and erythematous papules on the forearms, elbows, knees, and thighs and then developed right-leg weakness, difficulty with fine motor movement, and ptosis. Chest CT identified a right-lung spiculated nodule. Skin and pulmonary nodule biopsies showed lymphohistiocytic infiltrate with granulomatous features, without lymphoid cells, metastatic carcinoma or melanoma cells, or microorganisms. Epstein-Barr immunostain result was negative, making lymphomatoid granuloma unlikely. The inflammatory process involved the peripheral vasculature on FDG PET, and given the related neuropathy, findings were compatible with granulomatous vasculitis.

Abstract

A pilot study was performed in patients with recurrent back pain after spinal fusion surgery to evaluate the ability of (18)F-NaF PET/CT imaging to correctly identify those requiring surgical intervention and to locate a site amenable to surgical intervention.In this prospective study 22 patients with recurrent back pain after spinal surgery and with equivocal findings on physical examination and CT were enrolled for evaluation with (18)F-NaF PET/CT. All PET/CT images were prospectively reviewed with the primary objective of identifying or ruling out the presence of lesions amenable to surgical intervention. The PET/CT results were then validated during surgical exploration or clinical follow-up of at least 15 months.Abnormal (18)F-NaF foci were found in 16 of the 22 patients, and surgical intervention was recommended. These foci were located at various sites: screws, cages, rods, fixation hardware, and bone grafts. In 6 of the 22 patients no foci requiring surgical intervention were found. Validation of the results by surgery (15 patients) or on clinical follow-up (7 patients) showed that (18)F-NaF PET/CT correctly predicted the presence of an abnormality requiring surgical intervention in 15 of 16 patients and was falsely positive in 1 of 16.In this initial investigation, (18)F-NaF PET/CT imaging showed potential utility for evaluation of recurrent symptoms after spinal fusion surgery by identifying those patients requiring surgical management.

Abstract

This study aims to evaluate (64)Cu-DOTA-rituximab (PETRIT) in a preclinical transgenic mouse model expressing human CD20 for potential clinical translation.(64)Cu was chelated to DOTA-rituximab. Multiple radiolabeling, quality assurance, and imaging experiments were performed. The human CD20 antigen was expressed in B cells of transgenic mice (CD20TM). The mice groups studied were: (a) control (nude mice, n?=?3) that received 7.4 MBq/dose, (b) with pre-dose (CD20TM, n?=?6) received 2 mg/kg pre-dose of cold rituximab prior to PETRIT of 7.4 MBq/dose, and (c) without pre-dose (CD20TM, n?=?6) PETRIT alone received 7.4 MBq/dose. Small animal PET was used to image mice at various time points (0, 1, 2, 4, 24, 48, and 72 h). The OLINDA/EXM software was used to determine the human equivalent dose for individual organs.PETRIT was obtained with a specific activity of 545?±?38.91 MBq/nmole, radiochemical purity >95%, and immunoreactivity >75%. At 24 h, spleenic uptake of PETRIT%ID/g (mean?±?STD) with and without pre-dose was 1.76?±?0.43% and 16.5?±?0.45%, respectively (P value?=?0.01). Liver uptake with and without pre-dose was 0.41?±?0.51% and 0.52?±?0.17% (P value?=?0.86), respectively. The human equivalents of highest dose organs with and without pre-dose are osteogenic cells at 30.8?±?0.4 ?Sv/MBq and the spleen at 99?±?4 ?Sv/MBq, respectively.PET imaging with PETRIT in huCD20 transgenic mice provided human dosimetry data for eventual applications in non-Hodgkins lymphoma patients.

The Impact of Partial Volume Correction in the Evaluation of Solitary Pulmonary Nodules by FDG PET/CT in a Population at Intermediate Risk of Lung Cancer4th International Symposium on Targeted Radiotherapy and Dosimetry (ISTARD) in Conjunction with the 25th Annual Congress of the European-Association-of-Nuclear-Medicine (EANM)Keu, K., Nair, V. S., Mittra, E., Gambhir, S. S., Iagaru, A.SPRINGER.2012: S455?S455

Abstract

We previously showed that metabolic tumor volume (MTV) on positron emission tomography-computed tomography (PET-CT) predicts for disease recurrence and death in head-and-neck cancer (HNC). We hypothesized that increases in MTV over time would correlate with tumor growth and biology, and would predict outcome. We sought to examine tumor growth over time in serial pretreatment PET-CT scans.From 2006 to 2009, 51 patients had two PET-CT scans before receiving HNC treatment. MTV was defined as the tumor volume ? 50% of maximum SUV (SUV(max)). MTV was calculated for the primary tumor, nodal disease, and composite (primary tumor + nodes). MTV and SUV velocity were defined as the change in MTV or SUV(max) over time, respectively. Cox regression analyses were used to examine correlations between SUV, MTV velocity, and outcome (disease progression and overall survival).The median follow-up time was 17.5 months. The median time between PET-CT scans was 3 weeks. Unexpectedly, 51% of cases demonstrated a decrease in SUV(max) (average, -0.1 cc/week) and MTV (average, -0.3 cc/week) over time. Despite the variability in MTV, primary tumor MTV velocity predicted disease progression (hazard ratio 2.94; p = 0.01) and overall survival (hazard ratio 1.85; p = 0.03).Primary tumor MTV velocity appears to be a better prognostic indicator of disease progression and survival in comparison to nodal MTV velocity. However, substantial variability was found in PET-CT biomarkers between serial scans. Caution should be used when PET-CT biomarkers are integrated into clinical protocols for HNC.

Abstract

Diagnostic imaging plays a major role in the evaluation of patients with malignant bone disease. (18)F-Labeled sodium fluoride ((18)F NaF) is a positron-emitting radiopharmaceutical with desirable characteristics (rapid blood clearance and bone uptake) for high-quality functional imaging of the skeleton. In addition to higher sensitivity and specificity, (18)F NaF PET combined with computed tomography (PET/CT) allows for shorter imaging time, thus improving patients' convenience and benefiting the overall workflow of the imaging facility. Although as yet no robust evidence-based data exist, this article summarizes the published data currently available on the role of (18)F NaF PET/CT in the assessment of malignant bone disease.

Abstract

Technetium (Tc) methylene diphosphonate (MDP) has been the standard method for bone scintigraphy for three decades. (18)F sodium fluoride ((18)F NaF) positron emission tomography (PET)/computed tomography (CT) has better resolution and is considered superior. The role of 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F FDG) PET/CT is proven in a variety of cancers, for which it has changed the practice of oncology. There are few prospective studies comparing these three methods of detection of skeletal metastases. Thus, we were prompted to initiate this prospective pilot trial.This is a prospective study (Sep 2007-Dec 2010) of 52 patients with proven malignancy referred for evaluation of skeletal metastases. There were 37 men and 15 women, 19-84 years old (average, 55.6?±?15.9). Technetium-99m ((99m)Tc) MDP bone scintigraphy, (18)F NaF PET/CT, and (18)F FDG PET/CT were subsequently performed within 1 month.Skeletal lesions were detected by (99m)Tc MDP bone scintigraphy in 22 of 52 patients, by (18)F NaF PET/CT in 24 of 52 patients, and by (18)F FDG PET/CT in 16 of 52 patients. The image quality and evaluation of extent of disease were superior by (18)F NaF PET/CT over (99m)Tc MDP scintigraphy in all 22 patients with skeletal lesions on both scans and over (18)F FDG PET/CT in 11 of 16 patients with skeletal metastases on (18)F FDG PET/CT. In two patients, (18)F NaF PET/CT showed skeletal metastases not seen on either of the other two scans. Extraskeletal lesions were identified by (18)F FDG PET/CT in 28 of 52 subjects.Our prospective pilot-phase trial demonstrates superior image quality and evaluation of skeletal disease extent with (18)F NaF PET/CT over (99m)Tc MDP scintigraphy and (18)F FDG PET/CT. At the same time, (18)F FDG PET detects extraskeletal disease that can significantly change disease management. As such, a combination of (18)F FDG PET/CT and (18)F NaF PET/CT may be necessary for cancer detection. Additional evaluation with larger cohorts is required to confirm these preliminary findings.

Abstract

Typically, (18)F-FDG PET/CT and (18)F-NaF PET/CT scans are done as two separate studies on different days to allow sufficient time for the radiopharmaceutical from the first study to decay. This is inconvenient for the patients and exposes them to two doses of radiation from the CT component of the examinations. In the current study, we compared the clinical usefulness of a combined (18)F-FDG/(18)F-NaF PET/CT scan with that of a separate (18)F-FDG-only PET/CT scan.There were 62 patients enrolled in this prospective trial. All had both an (18)F-FDG-alone PET/CT scan and a combined (18)F-FDG/(18)F-NaF PET/CT scan. Of the 62 patients, 53 (85%) received simultaneous tracer injections, while 9 (15%) received (18)F-NaF subsequent to the initial (18)F-FDG dose (average delay 2.2 h). Images were independently reviewed for PET findings by two Board-Certified nuclear medicine physicians, with discrepancies resolved by a third reader. Interpreters were instructed to only report findings that were concerning for malignancy. Reading the (18)F-FDG-only scan first for half of the patients controlled for order bias.In 15 of the 62 patients (24%) neither the (18)F-FDG-only PET/CT scan nor the combined (18)F-FDG/(18)F-NaF PET/CT scan identified malignancy. In the remaining 47 patients who had PET findings of malignancy, a greater number of lesions were detected in 16 of 47 patients (34%) using the combined (18)F-FDG/(18)F-NaF PET/CT scan compared to the (18)F-FDG-only PET/CT scan. In 2 of these 47 patients (4%), the (18)F-FDG-only scan demonstrated soft tissue lesions that were not prospectively identified on the combined study. In 29 of these 47 patients (62%), the combined scan detected an equal number of lesions compared to the (18)F-FDG-only scan. Overall, 60 of all the 62 patients (97%) showed an equal or greater number of lesions on the combined scan than on the (18)F-FDG-only scan.The current study demonstrated that (18)F-FDG and (18)F-NaF can be combined in a single PET/CT scan by administering the two radiopharmaceuticals simultaneously or in sequence on the same day. In addition to patient convenience and reduced radiation exposure from the CT component, the combined (18)F-FDG/(18)F-NaF PET/CT scan appeared to increase the sensitivity for detection of osseous lesions compared to the (18)F-FDG-only PET/CT scan in the studied population.

Abstract

Oncolytic virotherapy poses unique challenges to the evaluation of tumor response. We hypothesized that the addition of [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) to standard computed tomography (CT) evaluation would improve diagnostic and prognostic power of the measurement of tumor response to oncolytic virotherapy. A phase I/II trial was conducted to investigate treatment of hepatic metastases from colorectal carcinoma using intra-arterial administration of the oncolytic herpes virus NV1020. Both contrast-enhanced CT and FDG PET were obtained on each patient at each time point. Quantitative FDG PET and CT responses were correlated with each other and with clinical outcome metrics. A majority of patients showed initial post-viral infusion increases in tumor size (69%) or in standardized uptake value (SUV) (80%) large enough to qualify as progressive disease. Most showed subsequent decreases in tumor size (64%) or SUV (83%) enough to be reclassified as partial response or stable disease. Late PET and CT imaging results correlated well with each other and with clinical outcomes, but results from early in the treatment scheme did not correlate with each other, with later results, or with clinical outcomes. The addition of FDG PET to the evaluation of tumor response to the oncolytic virus NV1020 did not provide useful diagnostic or prognostic data. More sophisticated molecular imaging will need to be developed to monitor the effects of this novel class of antineoplastic agents.

Abstract

Positron emission tomography (PET) is a highly sensitive, low invasive technology for cancer biology imaging. The role of F-18 FDG PET/CT in differentiated thyroid cancer (DTC) is well established, particularly in patients presenting with elevated Tg levels and negative radioactive iodine WBS. It has been demonstrated that F-18 FDG uptake represents less differentiated thyroid cancer cells or dedifferentiated cells and PET positive lesions are more likely to be resistant to I treatment. The uptake of F-18 FDG is related to tumor size, thyroid capsule invasion and histological variants with a poor prognosis. As in other cancers, early detection of recurrences improves outcomes and survival. I PET/CT can also be used to image the patients with DTC, similarly to I WBS. Compared with F-18 FDG PET/CT, its spatial resolution is only slightly degraded but increasing the imaging time reduces this difference. In addition, F-18 FDG PET/CT has been found helpful in the management of patients with anaplastic and medullary thyroid cancer. Other radiopharmaceuticals such as Ga-DOTATOC and F-18 DOPA may provide complimentary information to F-18 FDG PET/CT in the detection of recurrent thyroid cancer.

FDG-PET/CT in Cancers of the Head and Neck: What is the Definition of Whole Body Scanning?MOLECULAR IMAGING AND BIOLOGYIagaru, A., Mittra, E. S., Gambhir, S. S.2011; 13 (2): 362-367

Abstract

The role of 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET) was studied in a variety of cancers, including head and neck squamous cell carcinomas (HNSCC) and nasopharyngeal carcinomas (NPC), with several presentations indicating that for these clinical entities a "whole-body" (i.e., eyes to thighs) may yield little additional information. Therefore, we were prompted to review our experience with PET/computed tomography (CT) in the management of patients with HNSCC and NPC.This is a retrospective study of 133 patients with HNSCC, 23-90 years old (average: 58.2?±?12.7) and 26 patients with NPC, ages 16-75 (average: 47.3?±?17.1), who had whole body PET/CT at our institution from Jan 2003 to Nov 2006. Reinterpretation of the imaging studies for accuracy and data analysis from medical records was performed. Lesions identified on PET/CT below the level of the adrenal glands were recorded and tabulated.Lesions were identified below the adrenal glands in seven patients (5.2%) with HNSCC. These included hepatic and osseous metastases from HNSCC in two patients (1.5%), a new renal cancer (0.75%), a new pancreatic cancer (0.75%), a new colon cancer (0.75%) and findings proven benign on follow-up (focal colon uptake in one patient and an inflammatory inguinal lymph node in another patient; 1.5%). Lesions were identified below the adrenal glands in three patients (11.5%) with NPC. These included osseous metastases from NPC in two patients (7.7%) and findings proven benign on follow-up (focal colon uptake in one patient; 3.84%).This study suggests that whole body PET/CT imaging in HNSCC has a relatively low yield (3%, 95% CI: 1.33-8.42) of significant findings below the level of the adrenal glands. Therefore, implementing a more limited protocol (through the level of adrenal glands), especially in low-risk cases of HNSCC, may be considered. However, whole body PET/CT imaging in NPC may have a significant yield (7.7%, 95% CI: 1.02-25.26) of medically relevant findings below the level of the adrenal glands. Thus, the whole body (i.e., vertex to thighs) PET/CT scan of NPC patients appears to be the appropriate imaging protocol for this population. This recommendation requires further evaluation and validation in larger prospective studies.

Abstract

Stunning of thyroid tissue by diagnostic activities of (131)I has been described by some investigators and refuted by others. The support both for and against stunning has at times been enthusiastic and vigorous. We present the data from both sides of the debate in an attempt to highlight the strengths and deficiencies in the investigations cited. Clinical, animal, and in vitro studies are included. There are considerable differences in clinical practice, such as the administered activity for diagnostic whole-body scan, delay between diagnostic scan and treatment, time between treatment and posttherapy scanning, and timing of follow-up studies, that have to be analyzed with care. Other factors that often cannot be judged, such as levels of thyroid-stimulating hormone and serum iodine at time of diagnostic testing versus treatment could have an influence on stunning. Larger diagnostic doses and longer delays to therapy appear to increase the likelihood of stunning. The stunning effect of early-absorbed radiation from the therapy should also be considered.

Abstract

Utilizing novel imaging modalities for defining response and predicting long-term outcome after treatment may have a significant impact on cancer patient management. (18)F-FDG PET/CT has great potential for use in early assessment of response to cancer therapy. However, the lack of a general consensus on a specific set of response criteria makes adoption of PET difficult for the oncology community. The optimal time after initiating therapy for assessing response to treatment also has yet to be clearly determined.

Abstract

Radioimmunotherapy relies on the principles of immunotherapy, but expands the cytotoxic effects of the antibody by complexing it with a radiation-emitting particle. If we consider radioimmunotherapy as a step beyond immunotherapy of cancer, the step was prompted by the (relative) failure of the latter. The conventional way to explain the failure is a lack of intrinsic killing effect and a lack of penetration into poorly vascularized tumor masses. The addition of a radioactive label (usually a ?-emitter) to the antibody would improve both. Radiation is lethal and the type of radiation used (beta rays) has a sufficient range to overcome the lack of antibody penetration. At present, the most successful (and FDA approved) radioimmunotherapy agents for lymphomas are anti-CD20 monoclonal antibodies. Rituximab (Rituxan(®)) is a chimeric antibody, used as a non-radioactive antibody and to pre-load the patient when Zevalin(®) is used. Zevalin(®) is the Yttrium-90 ((90)Y) or Indium-111 ((111)In) labeled form of Ibritumomab Tiuxetan. Bexxar(®) is the Iodine-131 ((131)I) labeled form of Tositumomab. Ibritumomab Tiuxetan and Tositumomab are murine anti-CD20 monoclonal antibodies, not chimeric antibodies. Promising research is being done to utilize radioimmunotherapy earlier in the treatment algorithm for lymphoma, including as initial, consolidation, and salvage therapies. However, despite more than 8 years since initial regulatory approval, radioimmunotherapy still has not achieved widespread use due to a combination of medical, scientific, logistic, and financial barriers. Other experimental uses for radioimmunotherapy include other solid tumors to treat infections. Optimization can potentially be done with pre-targeting and bi-specific antibodies. Alpha particle and Auger electron emitters show promise as future radioimmunotherapy agents but are mostly still in pre-clinical stages.

Abstract

Imaging is critical for the proper evaluation of patients with primary tumors of bone. There is a growing role for (18)F-fluorodeoxyglucose PET and PET/computed tomography (CT) in the grading, staging, prognostication, evaluation of therapeutic response, and detection of recurrent disease in bone. These modalities can also be used to help differentiate benign from malignant disorders of bone.

Abstract

The American Cancer Society estimated 66,120 new cases of non-Hodgkin lymphoma (NHL) in the USA in 2008. Radioimmunotherapy has been shown in clinical trials to be an effective treatment for refractory/relapsed NHL. The available agents are Bexxar, a (131)I radiolabeled murine monoclonal antibody, and Zevalin, a (90)Y radiolabeled murine antibody. Both target CD20 receptors present on the surface of lymphocytes. We present our clinical experience with Bexxar and Zevalin in the management of low-grade refractory or relapsed NHL.This is a retrospective study (Jan 2000-Jul 2006) of 67 patients with NHL, who were treated with Bexxar (31 patients, group A) or Zevalin (36 patients, group B) for refractory/relapsed disease. Group A included 16 men and 15 women, 35-81 years old (average, 59.3 +/- 13.4). Group B included 27 men and nine women, 36-85 years old (average, 55.4 +/- 13.8). Therapeutic doses ranged 40-138 mCi (average, 78.1 +/- 28.2) for Bexxar and 17-34 mCi (average, 28.8 +/- 4.37) for Zevalin.Objective responses were induced in 22 of the 31 patients (70.9%) in group A and 28 of the 36 patients (77.8%) in group B. Complete response was noted in 11 patients (35.5%), partial response in seven patients (22.6%), and mixed response in four patients (12.9%) in group A. There were five patients (16.1%) with stable disease and four patients (12.9%) with disease progression in the same group. Complete response was noted in 15 patients (41.7%), partial response in nine patients (25%), and mixed response in four patients (11.1%) in group B. There were four patients (11.1%) with stable disease and another four patients (11.1%) with disease progression in the same group. The average decreases at posttherapy nadir were 36.9% +/- 0.33 (group A) and 52.6% +/- 0.32 (group B) for platelets, 27.8% +/- 0.27 (group A) and 34.2% +/- 0.38 (group B) for leukocytes, and 4.9% +/- 0.15 (group A) and 7.6% +/- 0.11 (group B) for hemoglobin. Grades 3 and 4 hematological toxicity occurred in 14 patients (45.2%) treated with Bexxar and 22 patients (61.1%) treated with Zevalin, but was reversible.Our study suggests that clinical practice of Bexxar and Zevalin radioimmunotherapy is an effective and safe adjunctive treatment for patients with NHL refractory/relapsed to conventional treatment. However, due to the small number of subjects, it was not possible to determine whether differences in the outcomes or toxicities from the two agents were statistically significant.

Abstract

Only a limited number of studies have evaluated the efficacy of 18F-FDG PET/CT for recurrent cervical carcinoma, which this study seeks to expand upon.This is a retrospective study of 30 women with cervical carcinoma who had a surveillance PET/CT after initial therapy. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated using a 2 × 2 contingency table with pathology results (76%) or clinical follow-up (24%) as the gold standard. The Wilson score method was used to perform 95% confidence interval estimations.The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of PET/CT for the detection of local recurrence at the primary site were 93, 93, 93, 86, and 96%, respectively. The same values for the detection of distant metastases were 96, 95, 95, 96, and 95%, respectively. Seventy-one percent of the scans performed in symptomatic patients showed true-positive findings. In comparison, 44% of scans performed in asymptomatic patients showed true-positive findings. But, all patients subsequently had a change in their management based on the PET/CT findings such that the effect was notable. The maximum standardized uptake value ranged from 5 to 28 (average: 13 ± 7) in the primary site and 3 to 23 (average: 8 ± 4) in metastases which were significantly different (p = 0.04).This study demonstrates favorable efficacy of 18F-FDG PET/CT for identification of residual/recurrent cervical cancer, as well as for localization of distant metastases.

Abstract

Anal squamous cell carcinoma (ASCC) is a rare cancer of the gastrointestinal tract, representing less than 5% of the digestive malignancies. The cytological and/or histological confirmation of a suspected lesion should be followed by a complete imaging evaluation to determine the extent of disease. We are presenting our experience with (18)F-FDG PET in ASCC. This is a retrospective case series of patients diagnosed and treated for ASCC at our institution(s). A total of 14 (18)F-FDG PET scans (8 for initial staging, 6 for evaluation of response to chemotherapy and radiation therapy) were performed in 8 patients (6 men, 2 women). The patients were 33-60 years old (average: 44+/-9). Our results showed that PET demonstrated the primary lesion at initial evaluation in 7 of 8 anal cancers and showed FDG- avid lymph nodes in 4 patients. Metastatic nodal involvement was confirmed by pathology in 2 patients; in the other 2 patients pathology showed reactive follicular hyperplasia. In another patient, follow-up PET demonstrated progression of disease despite treatment, prompting a change in disease management. In the remaining 5 patients with follow-up PET, the scans confirmed interval resolution of the (18)F-FDG uptake in the primary lesion, suggesting good treatment response. In conclusion, PET provides valuable diagnostic information in initial staging and evaluation of treatment response in ASCC that may significantly alter the clinical management. The emergence of the combined PET/CT scanner enhanced the accuracy of the imaging procedure in view of the precise anatomic localization of metabolic abnormalities.

Abstract

To prepare for yttrium-90 ((90)Y) microsphere radioembolization therapy, digital subtraction angiography (DSA) and technetium- 99m-labeled macroaggregated albumin ((99m)Tc MAA) scintigraphy are used for treatment planning and detection of potential nontarget embolization. The present study was performed to determine if cone-beam computed tomography (CBCT) affects treatment planning as an adjunct to these conventional imaging modalities.From March 2007 to August 2008, 42 consecutive patients (21 men, 21 women; mean age, 59 years; range, 21-75 y) who underwent radioembolization were evaluated by CBCT in addition to DSA and (99m)Tc MAA scintigraphy during treatment planning, and their records were retrospectively reviewed. The contrast-enhanced territories shown by CBCT with selective intraarterial contrast agent administration were used to predict intrahepatic and possible extrahepatic distribution of microspheres.In 22 of 42 cases (52%), extrahepatic enhancement or incomplete tumor perfusion seen on CBCT affected the treatment plan. In 14 patients (33%), the findings were evident exclusively on CBCT and not detected by DSA. When comparing CBCT versus (99m)Tc MAA scintigraphy, CBCT showed eight cases of extrahepatic enhancement (19%) that were not evident on (99m)Tc MAA imaging. CBCT findings directed the additional embolization of vessels or repositioning of the catheter for better contrast agent and microsphere distribution. One case of gastric ulcer from nontarget embolization caused by reader error was observed.CBCT can provide additional information about tumor and tissue perfusion not currently detectable by DSA or (99m)Tc MAA imaging, which should optimize (90)Y microsphere delivery and reduce nontarget embolization.

Abstract

(18)F-FDG PET/CT is used for detecting cancer and monitoring cancer response to therapy. However, because of the variable rates of glucose metabolism, not all cancers are identified reliably. Sodium (18)F was previously used for bone imaging and can be used as a PET/CT skeletal tracer. The combined administration of (18)F and (18)F-FDG in a single PET/CT study for cancer detection has not been reported to date.This is a prospective pilot study (November 2007-November 2008) of 14 patients with proven malignancy (6 sarcoma, 3 prostate cancer, 2 breast cancer, 1 colon cancer, 1 lung cancer, and 1 malignant paraganglioma) who underwent separate (18)F PET/CT and (18)F-FDG PET/CT and combined (18)F/(18)F-FDG PET/CT scans for the evaluation of malignancy (a total of 3 scans each). There were 11 men and 3 women (age range, 19-75 y; average, 50.4 y).Interpretation of the combined (18)F/(18)F-FDG PET/CT scans compared favorably with that of the (18)F-FDG PET/CT (no lesions missed) and the (18)F PET/CT scans (only 1 skull lesion seen on an (18)F PET/CT scan was missed on the corresponding combined scan). Through image processing, the combined (18)F/(18)F-FDG scan yielded results for bone radiotracer uptake comparable to those of the (18)F PET/CT scan performed separately.Our pilot-phase prospective trial demonstrates that the combined (18)F/(18)F-FDG administration followed by a single PET/CT scan is feasible for cancer detection. This combined method opens the possibility for improved patient care and reduction in health care costs.

Abstract

The role of F-FDG PET has been studied in ovarian carcinoma, but its sensitivity and specificity calculations are based on dedicated PET acquisition, not PET/CT in the majority of the published studies. Therefore, we were prompted to review our experience with PET/CT in the management of patients with ovarian carcinoma.This is a retrospective study of 43 women with ovarian carcinoma, 27-80 years old (average: 53.9+/-7.8), who had whole-body PET/CT at our institution from 1 January 2003 to 31 August 2006. We reviewed the patients' outcomes from medical records and compared them to the interpretation of the PET/CT scans. Sensitivity and specificity were calculated using a 2 x 2 table with pathology results (79.1% of the patients) or clinical follow-up (20.9% of the cases) as the 'gold standard'. Confidence interval (CI) estimations were performed using the Wilson score method.All patients had advanced stage ovarian cancer and the study was requested for re-staging. A total of 60 scans were performed: 30 patients had one scan, nine patients had two scans and four patients had three scans. The administered doses of F-FDG ranged from 381.1 to 769.6 MBq (average: 569.8+/-73.3). PET/CT had a sensitivity of 88.4% (95% CI: 75.1-95.4) and a specificity of 88.2% (95% CI: 64.4-97.9) for detection of ovarian cancer. The SUV max of the detected lesions ranged from 3 to 27 (average: 9.4+/-5.9). The CA-125 tumor marker ranged from 3 to 935 kU/ml (average: 265.2) in patients with positive scans and 4-139 kU/ml (average: 17.1) in patients with negative scans. This difference was statistically significant (P value: 0.0242).This study confirms the good results of F-FDG PET/CT for identification of residual/recurrent ovarian cancer, as well as for distant metastases localization. PET/CT should be an integral part in evaluation of patients with high-risk ovarian cancer or rising values of tumor markers (CA-125), prior to selection of the most appropriate therapy.

Abstract

Radioimmunotherapy is an effective treatment for non-Hodgkin's lymphoma (NHL). 90Y-ibritumomab is an antibody targeting CD20 receptors on the surface of lymphocytes. We present observations from our clinical experience with 90Y-ibritumomab in the management of NHL.This was a retrospective study of 28 NHL patients treated with 90Y-ibritumomab. There were 21 men and 7 women, 36-85 y old. A diagnostic dose of 111In-ibritumomab was administered on day 0, and imaging followed immediately and at 24, 48, and 72 h. The doses of 90Y-ibritumomab ranged from 629 to 1,258 MBq (17-34 mCi). Outcomes were compared with the findings of the 111In-ibritumomab scans.90Y-ibritumomab induced objective responses in 22 of 28 patients. A complete response was noted in 9 patients, a partial response in 9 patients, and a mixed response in 4 patients. Three patients had stable disease, and 3 patients had disease progression. 111In-ibritumomab findings were positive in 19 patients and negative in 9 patients. A complete response was noted in 2 of 19 patients with positive findings and 7 of 9 with negative findings. A partial response was seen in 7 of 19 patients with positive findings and 1 of 9 with negative findings. Disease progression was observed in 3 of 19 patients with positive findings and 0 of 9 with negative findings. The remaining patients had a mixed response or no changes.A higher rate of complete response after 90Y-ibritumomab treatment was seen in patients with negative 111In-ibritumomab findings, whereas a higher rate of disease progression despite therapy was noted in patients with positive 111In-ibritumomab findings. This observation suggests that patients with bulky disease may require more aggressive management.

Abstract

Assessing the response to treatment as soon after treatment initiation is one of the key reasons for imaging lymphoma patients. The optimal time after initiating treatment for assessing response to treatment has yet to be determined. Therefore, we were prompted to review our experience with serial (18)F-FDG PET/CT in patients undergoing treatment for Hodgkin's disease (HD) and non Hodgkin's lymphoma (NHL). This is a retrospective study (Feb 2003 - Oct 2004) of 20 patients, 11 men and 9 women, with age range of 7-75 years with diagnosis of HD (10) and NHL (10), who had PET/CT at our institution prior, during and at the completion of therapy. Restaging PET/CT was done after 2 cycles of chemotherapy in 10 patients (group A) and after 4 cycles of chemotherapy in 10 pts (group B). A total of 60 scans were reviewed. The DeltaSUV from baseline to first PET/CT was on average 67.6% in group A and 75.1% in group B. This had no statistical significance (P value: 0.31). The DeltaSUV from baseline to post-therapy PET/CT was on average 72.9% in group A and 79.8% in group B. This difference also had no statistical significance (P value: 0.24). The correlation coefficient was 0.98 in group A and 0.80 in group B. Results of PET/CT after 2 cycles of chemotherapy did not statistically differ from the results of PET/CT after 4 cycles of chemotherapy. These results need to be confirmed in larger, prospective, randomized trials.

Abstract

Successful treatment of Hodgkin lymphomas and non-Hodgkin lymphomas depends on accurate staging and prognostic estimations, as well as evaluation of response to therapy as early after initiation as possible. We focus on several aspects of molecular imaging and therapy that affect the management of patients who have lymphoma. First, we review prior use of gallium-67 citrate for evaluation of lymphoma patients, mainly from a historical perspective, since it was the mainstream lymphoma functional imaging tracer for decades. Next, we review current clinical uses of 18F Fluoro-2-Deoxyglucose (18F FDG) PET and PET/CT for evaluation of lymphoma patients and use of radioimmunotherapy in lymphoma. Finally, we discuss advances in molecular imaging that may herald the next generation of PET radiotracers after 18F FDG.

Abstract

F-18 FDG PET has been used to grade sarcomas and assess response to therapy in advanced disease. Certain chemotherapy agents are thought to induce an inflammatory response in the tumor bed that can make interpretation of post-therapy FDG PET scans difficult. A review of our experience with PET in assessing therapy response in osseous and soft tissue sarcomas (OSTS) is presented.This is a retrospective study (January 1999 to December 2004) of 14 patients with histologic diagnosis of OSTS, who had 2 consecutive PET examinations for evaluation of chemotherapy response. The group included 8 men and 6 women, with age range of 18 to 56 years (average, 36 +/- 14). Semiquantitative assessment of FDG uptake was performed by calculating maximum standard uptake value (SUVmax) before and after treatment. The response to therapy was assessed independently by tumor necrosis at post-therapy surgery and according to European Organization for Research and Treatment of Cancer (EORTC) criteria for PET. The follow-up PET examinations were performed at an interval of 28 to 166 days (average, 90 +/- 45). All patients ended the ifosfamide regimen at 7 to 36 (average, 16 +/- 9) days before the follow-up PET scans. Five of them received methotrexate, adriamycin, and/or cisplatin as well.Based on the EORTC criteria alone, 3 patients (21.4%) had progression of disease (increase in SUVmax of 29%-69%; mean, 48% +/- 20%), 5 patients (35.7%) had stable disease, and 6 patients (42.8%) had partial response (decrease in SUVmax of 27%-84%; mean, 62% +/- 23%). Across all patients, the tumor necrosis postchemotherapy ranged from 5% to 100% (mean, 64% +/- 34%). In 8 patients (57.1%) the tumor necrosis correlated with the SUVmax changes. However, for 3 patients, the SUVmax changes indicated partial response despite necrosis of fewer than 90% of the surgical specimens, whereas 3 patients with >90% tumor necrosis had SUVmax changes indicative of stable disease.The pathologically determined degree of necrosis postneoadjuvant chemotherapy was concordant with PET-assessed EORTC classification of response in 57.1% of the cases. However, a significant number of patients had discrepancies, which may be in part explained by chemotherapy-induced inflammation. The latter should be considered during post-therapy PET interpretation in OSTS.

Abstract

Intraoperative gamma probe guidance has become widely utilized for sentinel lymph node dissection in patients with breast cancer and melanoma, using (99m)Tc sulfur colloid. However, new indications are possible and need to continue to be investigated. We report the use during a wedge liver biopsy of a new hand-held gamma probe designed for (123)I intraoperative guidance. The patient studied is a 5-year-old boy with history of stage 4 high-risk neuroblastoma. Anatomic imaging (CT, MRI), (99m)Tc bone scintigraphy and 2-deoxy-2-[F-18]fluoro-d-glucose-positron emission tomography/computed tomography (FDG-PET/CT) were negative, but the (123)I MIBG scintigraphy suggested recurrent liver disease. A decision was made to biopsy these lesions to obtain histopathological confirmation. Intraoperative gamma probe mapping of the liver identified areas with signal above the background, but these were prove to be hemosiderin deposits on histo-pathology examination.

Abstract

The utility of 18-F-fluorodeoxyglucose-positron emission tomography (PET) and PET/CT for the evaluation of skull base tumors is incompletely investigated, as a limited number of studies specifically focus on this region with regard to PET imaging. Several patterns can be ascertained, however, by synthesizing the data from various published reports and cases of primary skull base malignancies, as well as head and neck malignancies that extend secondarily to the skull base, including nasopharyngeal carcinoma, nasal cavity and paranasal sinus tumors, parotid cancers, and orbital tumors.

Abstract

There are approximately 32,000 new cases of thyroid carcinoma annually in the United States. F-18 FDG PET/CT has an established role in cancer management, including thyroid cancer, usually in patients who are thyroglobulin (Tg) positive/iodine negative. We reviewed our experience with F-18 FDG PET/CT in thyroid cancer, with an emphasis on correlation with Tg, and maximum standardized uptake values (SUV). We also analyzed the role of thyroid stimulating hormone (TSH) on PET/CT results.This is a retrospective study (January 2003 to December 2006) of 76 patients with differentiated thyroid cancer, who had F-18 FDG PET/CT scans. There were 44 women and 32 men, with age range of 20 to 81 years (average, 51.1 +/- 18.1). The administered doses of F-18 FDG ranged from 396 to 717 MBq (15.8-19.4 mCi) (average, 566 +/- 74.8) (15.3 +/- 2). Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed.A total of 98 PET/CT scans were analyzed (59 patients had 1 scan, 12 patients had 2, and 5 patients had 3). PET/CT was 88.6% sensitive (95% CI: 78.-94.3) and 89.3% specific (95% CI: 71.9-97.1). Mean Tg level was 1203 ng/mL (range, 0.5-28,357) in patients with positive PET/CT and 9.72 ng/mL (range, 0.5-123.0) in patients with negative PET/CT scans (P = 0.0389). Mean SUV max was 10.8 (range, 2.5-32) in the thyroid bed recurrence/residual disease and 7.53 (range, 2.5-26.2) in metastatic lesions (P = 0.0114). Mean SUV max in recurrent/residual disease in patients with TSH =30 mIU/L was 9.3 (range, 2.5-34.1) and in patients with TSH >30 mIU/L was 8.1 (range, 2.6-32) (P = 0.2994).F-18 FDG PET/CT had excellent sensitivity (88.6%) and specificity (89.3%) in this patient population. Metastatic lesions were reliably identified, but were less F-18 FDG avid than recurrence/residual disease in the thyroid bed. TSH levels at the time of PET/CT did not appear to impact the FDG uptake in the lesions or the ability to detect disease. In the setting of high or rising levels of Tg, our study confirms that it is indicated to include PET/CT in the management of patients with differentiated thyroid cancer.

Abstract

This review focuses on several aspects of molecular imaging. First, current positron emission tomography (PET)/CT scanner technology and several novel imaging techniques that are being developed are briefly discussed. Next, current clinical indications for (18)F FDG PET and PET/CT that are relevant to the surgical oncologist are discussed. Finally, advances in molecular imaging that may herald the next generation of PET radiotracers beyond (18)F FDG are reviewed.

Abstract

In this review, the causes of thyrotoxicosis and the treatment of syndromes with increased trapping of iodine are discussed. The benefits and the potential side effects of 3 frequently used therapies--antithyroid medications, thyroidectomy, and (131)I treatment--are presented. The different approaches to application of (131)I treatment are described. Treatment with (131)I has been found to be cost-effective, safe, and reliable.

Abstract

2-deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET) has an established role in restaging of various cancers, including papillary and undifferentiated thyroid carcinoma. However, controversies exist regarding its ability to reliably assess recurrent medullary thyroid cancer (MTC). We were therefore prompted to review our experience with FDG-PET for detection of occult MTC.This is a retrospective study (Apr 1, 1997-Mar 31, 2004) of 13 patients with histologic diagnosis of MTC, who had PET examinations. The group included six men and seven women, 15-62 years old (average: 48+/-13). The PET scan request was triggered by rising levels of calcitonin and negative anatomical imaging studies.Recurrent/metastatic disease was identified by PET in seven (54%) of the 13 patients. The lesions were located in superior mediastinum (4), cervical lymph nodes (3), thyroid bed (2), lung (1) and liver (1). The calcitonin levels ranged from 52 to 5,090 pg/ml (average: 1,996 pg/ml) in patients with negative PET scans and from 132 to 9,500 pg/ml (average: 3,757 pg/ml) in patients with positive studies. The sensitivity and specificity of FDG-PET for disease detection in this cohort were 85.7% (95% CI: 48.7-97.4) and 83.3% (95% CI: 43.6-96.9), respectively.Our findings suggest a significant role for FDG-PET in patients with suspected MTC recurrence, with sensitivity of 85.7% and specificity of 83.3% for disease detection. FDG-PET provides additional information in a significant fraction of cases (54%) and could be used for restaging of patients with MTC and elevated levels of biomarkers (calcitonin). Additional studies are necessary to further evaluate the role of FDG-PET in MTC.

Abstract

We report the case of a 30 year-old man with previous history of melanoma and new diagnoses of localized abdominal Castleman's disease with a focus of follicular dendritic sarcoma within the Castleman's tumor. He presented soon after with a single enlarged abdominal lymph node characterized and followed-up by FDG PET/CT as a low grade malignancy consistent with Castleman's recurrence. However, other imaging techniques raised the possibility of sarcoma/ melanoma recurrence. Final surgical resection allowed histological confirmation of the FDG PET/CT findings. To our knowledge, this is one of the few cases in the literature of Castleman's disease and follicular dendritic sarcoma association in the same focus. This is the first paper to our knowledge to use FDG PET/CT as the follow-up imaging tool for serial characterization of recurrence of Castleman's disease and follicular dendritic sarcoma. FDG PET/CT may be useful in the differentiation between Castleman's disease and malignancies associated with this disease.

Abstract

18F FDG PET/CT is used for diagnosis, staging and establishing the response to therapy in various malignancies, including breast cancer (BC). Dedicated breast MRI (BMRI) is gaining a role in the management of BC patients (pts), demonstrating high sensitivity and specificity for detection of small lesions. We were therefore prompted to review our experience with PET and BMRI in BC.This is a retrospective study of 21 women with BC, 30-76 years old, who had BMRI and whole-body FDG PET/CT at our institution from Jun 2002 to May 2005. A total of 6 patients (group A) had BMRI and PET/CT in the preoperative period and 15 patients (group B) had BMRI and PET/CT after surgery. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed.For group A, BMRI identified breast lesions in 4 patients, while PET/CT was able to identify breast lesions in 5 patients. All these were proven to be malignancy on pathology examination. In group B, BMRI detected recurrent breast lesions in 8 patients, with 88.9% sensitivity and 83.3% specificity. In the same patient population, PET/CT was 33.3% sensitive and 91.7% specific. As a whole body examination, PET/CT revealed metastatic disease in 6 patients (100% sensitive and 90% specific). Overall, sensitivities and specificities for breast disease detection were 85.7% and 85.7% for BMRI, and 75% and 92.3% for 18F FDG PET/ CT.As expected, BMRI is more sensitive than PET/CT in the detection of breast lesions. However, PET/CT as a whole-body examination changed the management of disease by detection of distant lesions in 6 of the 21 patients. Our study suggests that 18F FDG PET/CT and BMRI should be considered as complimentary imaging tools in the pre- and postoperative work-up of patients diagnosed with breast cancer.

Abstract

2-Deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is widely available as a powerful imaging modality, combining the ability to detect active metabolic processes and their morphologic features in a single exam. The role of FDG-PET is proven in a variety of cancers, including melanoma, but the estimates of sensitivity and specificity are based in the majority of the published studies on dedicated PET, not PET/CT. Therefore, we were prompted to review our experience with FDG-PET/CT in the management of melanoma.This is a retrospective study on 106 patients with melanoma (20-87 years old; average: 56.8 +/- 15.9), who had whole-body FDG-PET/CT at our institution from January 2003 to June 2005. Thirty-eight patients (35.9%) were women and 68 patients (64.1%) were men. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed.All patients had the study for disease restaging. The primary tumor depth (Breslow's thickness) at initial diagnosis was available for 76 patients (71.7%) and ranged from 0.4 to 25 mm (average: 3.56 mm). The anatomic level of invasion in the skin (Clark's level) was determined for 70 patients (66%): 3, level II; 13, level III; 43, level IV; 11, level V. The administered dose of (18)F FDG ranged from 9.8 to 21.6 mCi (average: 15.4 +/- 1.8 mCi). FDG-PET/CT had a sensitivity of 89.3% [95% confidence interval (CI): 78.5-95] and a specificity of 88% (95% CI: 76.2-94.4) for melanoma detection.This study confirms the good results of FDG-PET/CT for residual/recurrent melanoma detection, as well as for distant metastases localization. PET/CT should be an integral part in evaluation of patients with high-risk melanoma, prior to selection of the most appropriate therapy.

Abstract

An adrenal metastasis was identified on an F-18 FDG PET/CT scan in a patient with anaplastic thyroid cancer. There are very few reports of thyroid cancer, even anaplastic thyroid cancer, metastasizing to the adrenal.

Abstract

Osseous and soft tissue sarcomas (OSTS) represent a histologic heterogeneous group of malignant tumors. Most of the current clinical data on the role of F-18 FDG PET in sarcomas come from patients studied with dedicated PET and less frequently with hardware fusion PET/CT. Therefore, we were prompted to review our experience with F-18 FDG PET/CT in OSTS.This is a retrospective study (January 2003-December 2005) of 44 patients with histologic diagnoses of OSTS who had F-18 FDG PET/CT at our institution. The group included 22 men and 22 women with an age range of 2 of 84 years (average, 37 +/- 20.2 years). The administered doses of F-18 FDG range 4.1 to 19.5 mCi (average, 14.3 +/- 3 mCi). Reinterpretation of the imaging studies for accuracy and data analysis from medical records was performed.The sensitivity and specificity of combined F-18 FDG PET/CT were 100% (95% confidence interval [CI] = 75.7-100) and 93.3% (95% CI = 78.7-98.1) for the primary OSTS, and 80% (95% CI = 58.4-91.9) and 86.4% (95% CI = 66.7-95.2) for metastases. When interpreted separately, CT outperformed PET for pulmonary metastases detection: CT was 76.5% sensitive and 88% specific, whereas PET was only 57.1% sensitive but 96.4% specific. For detection of other metastases, CT was 82.3% sensitive and 76% specific, with PET demonstrating 78.6% sensitivity and 92.8% specificity.Relatively similar results (except better specificity for PET and PET/CT) were noted when examining the rate of metastases detection, excluding pulmonary lesions. However, CT had a better detection rate for pulmonary metastases when compared with PET alone. A negative PET scan in the presence of suspicious CT findings in the chest cannot reliably exclude pulmonary metastases from OSTS.

Abstract

Sarcomas represent a significant therapeutic challenge and their potential for distant pulmonary metastases is well known. [(18)F]Fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) has a role in differentiating sarcomas from benign tumours and assessing the response to therapy in advanced sarcomas. However, PET appears to be less accurate in detection of pulmonary metastases. We were therefore prompted to review our experience with PET and PET/computed tomography (CT) in osseous and soft tissue sarcomas (OSTSs).This is a retrospective study (January 1995 to December 2004) of 106 patients with histological diagnosis of OSTS, who had PET and PET/CT at our institution. The group included 52 men and 54 women, aged 12-92 years (average, 45+/-20 years).For all the patients in the analysis, the sensitivity and specificity were 68.3% (95% CI: 53-80.4) and 98.4% (95% CI: 91.8-99.7) for PET, with 95.1% sensitivity (95% CI: 83.8-98.6) and 92.3% specificity (95% CI: 83.2-96.7) for CT. Pulmonary metastases were seen in 40 patients. CT identified 17 lesions larger than 1.0 cm, while PET identified 13 of them (76.5%).Chest CT is more sensitive than PET in detecting pulmonary metastases from OSTS. A significant portion of known pulmonary metastases greater than 1.0 cm on CT, are PET negative. Sub-centimetre CT lesions should not be considered false positive if inactive on PET. A negative PET scan in the presence of suspicious CT findings in the chest cannot reliably exclude pulmonary metastases from OSTS.

Abstract

2-Deoxy-2-[F-18]fluoro-D-glucose positron emission tomography (FDG-PET) has an established role in restaging of various cancers, including papillary and undifferentiated thyroid carcinoma, but detection rates are variable in the published literature. We were therefore prompted to review our experience with FDG-PET in detection of recurrent papillary thyroid cancer (PTC).This is a retrospective study (April 1, 1995-March 31, 2005) of 21 patients with histologic diagnosis of PTC who had PET examinations. The group included seven men and 14 women, with age range of 26-75 years (average 50 +/- 16). The PET scan request was triggered by rising levels of thyroglobulin (Tg) in the presence of a negative iodine-131 scan.Recurrent/metastatic disease was identified by PET in 16 (76%) of the 21 patients with PTC. The sensitivity and specificity of FDG-PET for disease detection in this cohort were 88.2% [95% confidence interval (CI), 65.7-96.7] and 75% (95% CI, 30.1-95.4), respectively. The Tg levels were 1.0-10.4 ng/ml (average, 4.52 ng/ml) in the patients with negative PET scans and 1.0-38 ng/ml (average, 16.8 ng/ml) in patients with positive scans. The lesions were located in the cervical lymph nodes (8), thyroid bed (4), lungs (4), and mediastinal lymph nodes (2).Our study confirms the feasibility of PET in detection of residual/recurrence of PTC, with sensitivity of 88.2% (95% CI, 65.7-96.7) and specificity of 75% (95% CI, 30.1-95.4). Detectable levels of Tg, even in the presence of negative I-131 scan or anatomic imaging, should prompt restaging with FDG-PET.

Abstract

2-Deoxy-2-[F-18]fluoro-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is becoming widely available as a powerful imaging modality, combining the ability to detect active metabolic processes and their morphologic features in a single study. The role of FDG-PET/CT is proven in lymphoma, melanoma, colorectal carcinoma, and other cancers. However, there are rare malignancies such as Merkel cell carcinoma that can potentially be evaluated with PET/CT. We were therefore prompted to review our experience with FDG-PET/CT in the management of patients with Merkel cell carcinoma.This is a retrospective case series of six patients with Merkel cell carcinoma, 58-81 years old (average 69 +/- 8.3), who had whole-body PET/CT at our institution from January 1st, 2003 to August 31st, 2005. Two patients were women and four were men. Reinterpretation of the imaging studies for accuracy and data analysis from medical records were performed.Twelve examinations were acquired for the six patients (one patient had six PET/CT, one patient had two PET/CT, and four patients had one PET/CT). The injected FDG doses ranged 381.1-669.7 MBq (average 573.5 +/- 70.3). Four patients had the PET/CT as part of initial staging, and two patients had the exam for restaging (after surgery and XRT). A total of six Merkel lesions (pancreas, adrenal, lip, submandibular lymph nodes, cervical lymph nodes, and parapharyngeal soft tissue) were identified in three patients and confirmed on histopathological examination. The FDG uptake in these areas was intense, with maximum standardized uptake value (SUVmax) values of 5-14 (average 10.4 +/- 3.8). In one patient, the PET/CT scan identified abnormal focal distal sigmoid uptake that was biopsied and diagnosed as adenocarcinoma. Two patients had negative scans and had no clinical evidence of disease on follow-up office visits (up to one year after PET/CT).This case series suggests that FDG-PET/CT may have a promising role in the management of patients with Merkel cell carcinoma.

Abstract

We report the positron emission tomography-computed axial tomography (PET-CT) appearance of the inflammatory involvement of the salivary glands of a 69-year-old female with a history of lymphoma and known primary Sjogren's syndrome. Hybrid PET-CT was performed 5 months after completion of chemotherapy using a Siemens Biograph scanner (Knoxville, TN) 45 minutes after intravenous administration of 15 mCi of F-18 fluorodeoxyglucose (FDG). CT transmission scan was obtained for attenuation correction. PET-CT demonstrated no evidence of hypermetabolic nodal disease but showed symmetric intensely hypermetabolic submandibular and parotid salivary glands.